JP3616816B2

JP3616816B2 - Hull resistance reduction device

Info

Publication number: JP3616816B2
Application number: JP2002059469A
Authority: JP
Inventors: 良孝右近; 敏幸加納; 孝則日野; 勝辻本; 英幹川島
Original assignee: National Maritime Research Institute
Current assignee: National Maritime Research Institute
Priority date: 2002-03-05
Filing date: 2002-03-05
Publication date: 2005-02-02
Anticipated expiration: 2022-03-05
Also published as: JP2003252284A

Description

【０００１】
【発明の属する技術分野】
本発明は、船舶の主機関から排出される高温の排気ガスを利用して、航走時における水面下の船体外板面に沿う粘性抵抗を減少させるようにした船体抵抗軽減装置に関する。
【０００２】
【従来の技術】
航走時における船体抵抗の軽減を図る手段として、船首部の船底外板部に設けられた多孔板から気泡を放出するようにしたものが開発されているが、このような気泡の放出のためには大容量のポンプが必要になるほか、多孔板の目詰まりを清掃するメンテナンスが必要になるという不具合がある。
【０００３】
【発明が解決しようとする課題】
そこで本発明は、船舶の主機関（特にガスタービン）から排出される排気ガスが著しく高温であることに着目し、この排気ガスとの熱交換により水面下の船体外板に沿う外水の境界層を加熱して、船体の受ける粘性抵抗を減少させるようにした装置を提供することを課題とする。
【０００４】
【課題を解決するための手段】
前述の課題を解決するため、本発明の船体抵抗軽減装置は、船舶の主機関から排出される高温の排気ガスの排出流路の途中にダクトが介装されて、同ダクトが水面下における船体外板を加熱すべく同外板の内面に沿い配設されるとともに、同ダクトの船内側の壁部に断熱材が施され、航行時に上記ダクトにより加熱された上記船体外板の外面に沿い相対的に流れる外水を加熱して、同外水による船体の粘性抵抗を軽減するための航行時外板温度制御手段が設けられたことを特徴としている。
【０００５】
また、本発明の船体抵抗軽減装置は、上記航行時外板温度制御手段が、上記船体外板に沿う外水の沸騰によりマイクロバブルを発生させるための制御系を備えていることを特徴としている。
【０００６】
さらに、本発明の船体抵抗軽減装置は、上記航行時外板温度制御手段が、上記船体外板に沿う外水の沸騰蒸発により同船体外板に沿って気膜を発生させるための制御系を備えていることを特徴としている。
【０００７】
上述の本発明の船体抵抗軽減装置では、船舶の主機関における排気ガスの排出流路の途中に介装されたダクトが、水面下の船体外板に沿い配設されて、同ダクトを通る高温の上記排気ガスにより上記船体外板が加熱され、その際、船速や外水温度などの情報を受ける航行時外板温度制御手段を介し、上記船体外板の温度が、同船体外板に沿う外水の境界層において船体の受ける粘性抵抗を効率よく低減するように制御される。
【０００８】
そして、上記航行時外板温度制御手段が、上記船体外板に沿う外水の沸騰によりマイクロバブルを発生させるための制御系を備えていると、上記船体外板が上記マイクロバブルで覆われるようになって、船体の受ける粘性抵抗が的確に減少するようになる。
【０００９】
また、上記航行時外板温度制御手段が、上記船体外板に沿う外水の盛んな沸騰蒸発により同船体外板に沿って気膜を発生させるための制御系を備えて、同船体外板を更に高温に維持するように構成されていると、同船体外板に沿う気膜が安定した状態に保たれて、船体の受ける粘性抵抗を効率よく且つ大幅に減少させることができる。
【００１０】
さらに、本発明の船体抵抗軽減装置は、上記の水面下における船体外板が、上記ダクトの外水側の壁部を兼ねていることを特徴としている。
【００１１】
そして、本発明の船体抵抗軽減装置は、上記ダクトの外水側の壁部内面に、上記排気ガスの流れを分岐させて同排気ガスの熱を上記船体外板に伝達するための多数の分岐流路が互いに平行に列設されていることを特徴としている。
【００１２】
上述のように、高温の排気ガスを流通させる上記ダクトの外水の壁部として船体外板が兼ねていると、同船体外板の加熱が上記排気ガスにより直接行われるので、熱伝達の効率が著しく向上するようになる。
【００１３】
そして、上記ダクトの外水側の壁部内面に、上記排気ガスの流れを分岐させて同排気ガスの熱を上記船体外板に伝達しうる多数の分岐流路が互いに平行に列設されていると、上記船体外板への排気ガスの熱の伝達が一層効率よく行われるようになる。
【００１４】
また本発明の船体抵抗軽減装置は、上記の水面下における船体外板が、上記ダクトの外水側の壁部を兼ねるとともに、上記ダクトの外水側の壁部内面に、上記排気ガスの流通方向に沿う多数の吸熱用フィンが互いに平行に立設されていることを特徴としている。
【００１５】
このように、排気ガスによって直接加熱を受ける船体外板が、多数の吸熱用フィンを互いに平行に立設されていると、排気ガスの流通を妨げることなく同排気ガスから上記船体外板への熱の伝達が上記フィンを介して効率よく行われるようになる。
【００１６】
さらに、本発明の船体抵抗軽減装置は、船舶の航走時に船体外板に沿う水の流れが剥離を起こして乱流を生じやすい船首肩部，船尾肩部，船首バルブ弯曲部あるいは船底ビルジ部の内側に上記ダクトが設けられていることを特徴としており、これにより上記ダクトを通る排気ガスの高温度で、船首肩部や船尾肩部，船首バルブ弯曲部あるいは船底ビルジ部の船体外板面に沿う水の粘性を低下させたり、マイクロバブルや気膜を発生させたりして、船体抵抗の大幅な低減をもたらすことができる。
【００１７】
また、本発明の船体抵抗軽減装置は、上記ダクトとして船底部に二重底部分が構成され、停泊時に船底外板の外面温度を生物付着抑制温度に保持するための停泊時外板温度制御手段が設けられたことを特徴としている。
【００１８】
上述のように、主機関の高温度の排気ガスを導入されるダクトとして船底部に二重底部分が形成されると、カキや海草などの海洋生物の付着が防止されるが、特に停泊時に船底外板の外面温度を生物付着抑制温度に保持するための停泊時外板温度制御手段が設けられていると、船底面への海洋生物の付着が的確に防止できるようになる。
【００１９】
【発明の実施の形態】
以下、図面により本発明の実施形態について説明すると、図１は本発明の第１実施形態としての船体抵抗軽減装置を模式的に示す船体側面図、図２は図１のＡ−Ａ矢視拡大断面図であり、図３は本発明の第２実施形態としての船体抵抗軽減装置を模式的に示す船体側面図、図４は図３のＢ−Ｂ矢視拡大断面図であり、図５は本発明の第３実施形態としての船体抵抗軽減装置を模式的に示す船体側面図、図６は図５のＣ−Ｃ矢視拡大断面図、図７は図５のＤ−Ｄ矢視拡大断面図であり、図８は上記の各実施形態におけるダクトの変形例を示す断面図、図９は上記ダクトの他の変形例を示す断面図であり、図１０は本発明の第４実施形態としての船体抵抗軽減装置を示す船体横断面図である。
【００２０】
まず、本発明の第１実施形態について説明すると、図１に示すように、内航船としての船舶１の内部に、ガスタービンとしての主機関２が設置されて、同主機関２により駆動される発電機３からの電力により、電動機４を介して推進器５が作動するように構成されており、余剰電力は、バッテリー６に蓄えられて、船内の照明などに用いられるようになっている。
【００２１】
この内航船では、特に排気ガスの温度が６００°Ｃにも達するガスタービンとしての主機関２の特性を利用できるように、その排気ガスによって、船体の航行中に外水から受ける粘性抵抗の軽減が図られている。
【００２２】
すなわち、図１および図２に示すように、主機関２から排気管７を通じて導かれる高温の排気ガスが、水面下における船体外板（船底外板）を加熱できるように、船体外板８の内面に沿うダクト９へ導かれてから、さらに２次排気管７ａを通じて煙突１０より排出されるようになっている。
【００２３】
そして、航行中にダクト９における船体外板８の加熱温度が、同外板８に接する外水を沸騰させてマイクロバブルを発生させるのに適した温度（例えば２００〜３００°Ｃ）となるように、航行時外板温度制御手段１１が設けられており、同制御手段１１は、ダクト９の手前で排気管７に接続された分岐排気管７ｂへの分岐流量を調整する切替バルブ１２の制御を、船速，外水温度およびダクト９における船体外板温度の各検出センサからの検出信号に応じて行い、船体外板８に沿う外水の沸騰によりマイクロバブルを発生させるための制御系を備えている。
【００２４】
ダクト９は、船体外板８に沿い別体として設けられてもよいが、本実施形態では、ダクト９の外水側の壁部を船体外板８が兼ねていて、同ダクト９の船内側の壁部には断熱材１５が施されている。
【００２５】
ダクト９の内部は、排気管７に接続された管寄せ部９ａから２次排気管７ａに接続された管寄せ部９ｂへ到る多数の分岐管９ｃを備えて構成されており、各分岐管９ｃは船体外板８の内面に密着するように配置されている。
【００２６】
なお、ダクト９の構造としては、図８（横断面図）に示すように、排気管７を通じダクト９の内部に導入された排気ガスによって船体外板８が直接加熱されるようにしてもよく、ダクト９の内部には同ダクト内の排気ガスの整流と船体外板８への熱伝達度の向上とを図るための吸熱用フィン１３が船体外板８の内面に溶接される。
【００２７】
また、ダクト９の構造として、図９（横断面図）に示すように、排気管７に接続された管寄せ部９ａから２次排気管７ａ（図１参照）に接続された管寄せ部９ｂ（図１参照）へ到る多数の分岐流路９ｄを設け、同流路９ｄの壁部の一部として船体外板８を利用するようにしてもよく、この場合も排気ガスが直接船体外板８の内面に接触するので熱伝達の向上をもたらすことができる。
【００２８】
上述の第１実施形態の船体抵抗軽減装置では、船舶１の主機関２における排気ガスの排出流路の途中に介装されたダクト９が、水面下の船体外板８に沿い配設されて、同ダクト９を通る高温の上記排気ガスにより船体外板８が加熱され、その際、船速や外水温度などの情報を受ける航行時外板温度制御手段１１を介し、船体外板８の温度が、同船体外板８に沿う外水の境界層において船体の受ける粘性抵抗を効率よく低減するように制御される。
【００２９】
そして、航行時外板温度制御手段１１が、船体外板８に沿う外水の沸騰によりマイクロバブルを発生させるための制御系を備えているので、船体外板８が上記マイクロバブルで覆われるようになって、船体の受ける粘性抵抗が的確に減少するようになる。
【００３０】
次に、本発明の第２実施形態としての船体抵抗軽減装置について説明すると、図３に示すように本実施形態の場合も、内航船としての船舶１の内部に、ガスタービンとしての主機関２が設置されて、同主機関２により駆動される発電機３からの電力により、電動機４を介して推進器５が作動するように構成されており、余剰電力は、バッテリー６に蓄えられて、船内の照明などに用いられるようになっている。
【００３１】
そして、高温の排気ガスを排出するガスタービンとしての主機関２の特性を利用できるように、その排気ガスによって、船体の航行中に外水から受ける粘性抵抗の軽減が図られている。
【００３２】
また、図３および図４に示すように、主機関２から排気管７を通じて導かれる高温の排気ガスが、水面下における船体外板（船底外板）を加熱できるように、船体外板８の内面に沿うダクト９へ導かれてから、さらに２次の排気管７ａを通じて煙突１０より排出されるようになっているが、この第２実施形態では、特に航行中にダクト９における船体外板８の加熱温度が同外板８に接する外水の沸騰蒸発により同外板８に沿って気膜を発生させるのに適した温度（例えば３５０〜４５０°Ｃ）となるように、航行時外板温度制御手段１１Ａが設けられている。すなわち、この航行時外板温度制御手段１１Ａは、ダクト９の手前で排気管７に接続された分岐排気管７ｂへの分岐流量を調整する流量切替バルブ１２の制御を、船速，外水温度およびダクト９における船体外板温度の各検出センサからの検出信号に応じて行い、船体外板８に沿う外水の沸騰蒸発により同外板８に沿い気膜を発生させるための制御系を備えている。
【００３３】
そして、ダクト９の内部は、排気管７に接続された管寄せ部９ａから２次排気管７ａに接続された管寄せ部９ｂへ到る多数の分岐管９ｃを備えて構成されており、各分岐管９ｃは船体外板８の内面に密着するように配置されているが、本実施形態の場合も、ダクト９の構造として、図８に示されたものや、図９に示されたものを採用することができる。
【００３４】
上述の第２実施形態では、航行時外板温度制御手段１１Ａが、主機関２の排気ガスの有する高温度を利用して水面下の船体外板８を十分に加熱し、同外板８に沿う外水の盛んな沸騰蒸発により、同船体外板を気膜で覆うようにする制御系を備えているので、船体外板に沿う気膜が安定した状態に保たれて、航行中に船体の受ける粘性抵抗を効率よく且つ大幅に減少させることができる。
【００３５】
なお、この第２実施形態では、図４に示すように、排気管７に接続されたダクト９の管寄せ部９ａから左右へ制御弁１４を介して船底凹部８ａ内へ排気ガスの一部を噴出する手段が設けられており、その噴出ガスは船体外板８の外面を覆う粘性抵抗軽減用のバブルとなるが、制御弁１４の開度調整や閉鎖などの制御を航行時外板温度制御手段１１Ａにより行うようにしてもよい。
【００３６】
次に、本発明の第３実施形態としての船体抵抗軽減装置について説明すると、図５に示すように本実施形態の場合も、前述の第２実施形態と同様に、内航船としての船舶１の内部に、ガスタービンとしての主機関２が設置されて、同主機関２により駆動される発電機３からの電力により、電動機４を介して推進器５が作動するように構成されており、余剰電力は、バッテリー６に蓄えられて、船内の照明などに用いられるようになっている。
【００３７】
そして、高温の排気ガスを排出するガスタービンとしての主機関２の特性を利用できるように、その排気ガスによって、船体の航行中に外水から受ける粘性抵抗の軽減が図られている。
【００３８】
また、図５および図６に示すように、主機関２から排気管７を通じて導かれる高温の排気ガスが、水面下における船体外板（船底外板）を加熱できるように、船体外板８の内面に沿うダクト９へ導かれてから、さらに２次の排気管７ａを通じて煙突１０より排出されるようになっているが、この第３実施形態では、特に船体の船首肩部，船尾肩部および船首バルブ弯曲部においても、水面下の船体外板８を加熱して粘性抵抗を軽減するためのダクト９Ａ，９Ｂ，９Ｅが設けられていて、同ダクト９Ａ，９Ｂ，９Ｅに、それぞれ排気管７，７ａから分配制御弁１２ａ，１２ｂ，１２ｃを介し分岐した分岐配管７ｃ，７ｄ，７ｅを通じて高温の排気ガスが供給されるようになっている。
【００３９】
そして、各ダクト９Ａ，９Ｂ，９Ｅの断面は図７に示すように構成され、各ダクト９Ａ，９Ｂ，９Ｅの外水側の壁部は船体外板８が兼ねていて、船内側の壁部には断熱材１５ａが設けられている。また、各ダクト９Ａ，９Ｂ，９Ｅ内において、船体外板８には熱交換と整流作用とを行う吸熱用フィン１３ａが立設されている。
【００４０】
さらに、船底部の船体外板８に沿うダクト９内には、排気管７に接続された管寄せ部９ａから２次排気管７ａに接続された管寄せ部９ｂへ到る多数の分岐管９ｃが設けられているが、このダクト９内の構造についても、前述の図８や図９に示されるものが採用されてもよい。
【００４１】
また、航行中において、ダクト９における船体外板８の加熱温度が同外板８に接する外水の沸騰蒸発により同外板８に沿って気膜を発生させるのに適した温度（例えば３５０〜４５０°Ｃ）となるように、航行時外板温度制御手段１１Ａが設けられていて、この航行時外板温度制御手段１１Ａは、ダクト９の手前で排気管７に接続された分岐排気管７ｂへの分岐流量を調整する流量切替バルブ１２の制御を、船速，外水温度およびダクト９における船体外板温度の各検出センサからの検出信号に応じて行い、船体外板８に沿う外水の沸騰蒸発により同外板８に沿い気膜を発生させるための制御系を備えている。
【００４２】
そして、船首肩部，船尾肩部および船首バルブ弯曲部に沿うダクト９Ａ，９Ｂ，９Ｅについても、排気管７，７ａからの排気ガス流入量を調整して外板温度を所要の高温度に保てるように、分配制御弁１２ａ，１２ｂ，１２ｃの制御を行う航行時外板温度制御手段１１Ｂ，１１Ｃ，１１Ｅが設けられている。
【００４３】
上述の第３実施形態の船体抵抗軽減装置では、前述の第２実施形態の船体抵抗軽減装置と同様の作用効果が得られるほか、航行中に船体に沿う相対的な外水の流れの剥離を起こしやすい船首肩部や船尾肩部，船首バルブ弯曲部についても粘性抵抗を軽減するダクト９Ａ，９Ｂ，９Ｅが設けられているので、船舶全体として航行中に相対水流から受ける粘性抵抗の大幅な軽減が可能となり、船速の増加や燃料消費率の改善がもたらされるようになる。
【００４４】
次に、本発明の第４実施形態としての船体抵抗軽減装置について説明すると、図１０に示すように、船舶１に搭載されたガスタービンとしての主機関２からの排気ガスが、排気管７を通じ煙突１０から排出される前に、船体両側のビルジ部における船体外板８に沿って配設されたダクト９Ｃや、二重船底外板８ｂの隙間としてのダクト９Ｄを経由するように構成されており、各ダクト９Ｃ，９Ｄの船内側壁部にのみ断熱材１５が施されている。
そして、排気ガスを排気管７から直接煙突１０へ向かわせる２次排気管７ａとの間に流量切替バルブ１２が設けられている。
【００４５】
この第４実施形態では、航行中に各ダクト９Ｃ，９Ｄに通じる高温の排気ガスによって同ダクトにおける船体外板８を加熱し、同外板８に接する外水を高温にするかまたは沸騰させて粘性抵抗の減少を図る一方、船底外板については、船舶の停泊中においてもダクト９Ｄに排気ガスを通して生物付着抑制温度（７０〜９０°Ｃ）に保持することにより、海草やカキなどの海洋生物の付着を防止できるようになっており、このための停泊時外板温度制御手段１１Ｄが、流量切替バルブ１２や船底部のダクト９Ｄに接続された排気管の分配制御弁１２ｄの制御を行う制御系を備えて構成されている。
【００４６】
このようにして、この第４実施形態の船体抵抗軽減装置を備えることにより、巡航時の船体抵抗の大幅な軽減がもたらされるとともに、停泊時におけるカキや海草などの海洋生物の付着が防止されて、低速航行時の船体摩擦抵抗の減少や船底部外面のメンテナンスの簡易化がもたらされるようになる。
【００４７】
【発明の効果】
以上詳述したように、本発明の船体抵抗軽減装置によれば次のような効果が得られる。
（１）船舶の主機関における排気ガスの排出流路の途中に介装されたダクトが、水面下の船体外板に沿い配設されて、同ダクトを通る高温の上記排気ガスにより上記船体外板が加熱され、その際、船速や外水温度などの情報を受ける航行時外板温度制御手段を介し、上記船体外板の温度が、同船体外板に沿う外水の境界層において船体の受ける粘性抵抗を効率よく低減するように制御される。
（２）上記航行時外板温度制御手段が、上記船体外板に沿う外水の沸騰によりマイクロバブルを発生させるための制御系を備えていると、上記船体外板が上記マイクロバブルで覆われるようになって、船体の受ける粘性抵抗が的確に減少するようになる。
（３）上記航行時外板温度制御手段が、上記船体外板に沿う外水の盛んな沸騰蒸発により同船体外板に沿って気膜を発生させるための制御系を備えて、同船体外板を更に高温に維持するように構成されていると、同船体外板に沿う気膜が安定した状態に保たれて、船体の受ける粘性抵抗を効率よく且つ大幅に減少させることができる。
（４）高温の排気ガスを流通させる上記ダクトの外水の壁部として船体外板が兼ねていると、同船体外板の加熱が上記排気ガスにより直接行われるので、熱伝達の効率が著しく向上するようになる。
（５）上記ダクトの外水側の壁部内面に、上記排気ガスの流れを分岐させて同排気ガスの熱を上記船体外板に伝達しうる多数の分岐流路が互いに平行に列設されていると、上記船体外板への排気ガスの熱の伝達が一層効率よく行われるようになる。
（６）排気ガスによって直接加熱を受ける船体外板が、多数の吸熱用フィンを互いに平行に立設されていると、排気ガスの流通を妨げることなく同排気ガスから上記船体外板への熱の伝達が上記フィンを介して効率よく行われるようになる。
（７）船舶の航走時に船体外板に沿う水の流れが剥離を起こして乱流を生じやすい船首肩部，船尾肩部，船首バルブ弯曲部あるいは船底ビルジ部の内側に上記ダクトが設けられていると、上記ダクトを通る排気ガスの高温度で、船首肩部や船尾肩部，船首バルブ弯曲部あるいは船底ビルジ部の船体外板面に沿う水の粘性を低下させたり、マイクロバブルや気膜を発生させたりして、船体抵抗の大幅な低減をもたらすことができる。
（８）主機関の高温度の排気ガスを導入されるダクトとして船底部に二重底部分が形成されると、カキや海草などの海洋生物の付着が防止されるが、特に停泊時に船底外板の外面温度を生物付着抑制温度に保持するための停泊時外板温度制御手段が設けられていると、船底面への海洋生物の付着が的確に防止できるようになる。
【図面の簡単な説明】
【図１】本発明の第１実施形態としての船体抵抗軽減装置を模式的に示す船体側面図である。
【図２】図１のＡ−Ａ矢視拡大断面図である。
【図３】本発明の第２実施形態としての船体抵抗軽減装置を模式的に示す船体側面図である。
【図４】図３のＢ−Ｂ矢視拡大断面図である。
【図５】本発明の第３実施形態としての船体抵抗軽減装置を模式的に示す船体側面図である。
【図６】図５のＣ−Ｃ矢視拡大断面図である。
【図７】図５のＤ−Ｄ矢視拡大断面図である。
【図８】上記の各実施形態におけるダクトの変形例を示す断面図である。
【図９】上記ダクトの他の変形例を示す断面図である。
【図１０】本発明の第４実施形態としての船体抵抗軽減装置を示す船体横断面図である。
【符号の説明】
１船舶
２主機関
３発電機
４電動機
５推進器
６バッテリー
７排気管
７ａ２次排気管
７ｃ〜７ｅ分岐配管
８ａ船底凹部
８ｂ二重船底外板
９，９Ａ〜９Ｅダクト
９ａ，９ｂ管寄せ部
９ｃ分岐管
９ｄ分岐流路
１０煙突
１１，１１Ａ〜１１Ｅ航行時外板温度制御手段
１２流量切替バルブ
１２ａ〜１２ｄ分配制御弁
１３，１３ａ吸熱用フィン
１４制御弁
１５，１５ａ断熱材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hull resistance reducing apparatus that uses high-temperature exhaust gas discharged from a main engine of a ship to reduce a viscous resistance along a hull outer plate surface under water when traveling.
[0002]
[Prior art]
As a means to reduce hull resistance at the time of sailing, a device has been developed in which bubbles are released from a perforated plate provided in the bottom shell plate at the bow. In addition to requiring a large-capacity pump, there is a problem that maintenance for cleaning clogged perforated plates is required.
[0003]
[Problems to be solved by the invention]
Accordingly, the present invention focuses on the fact that the exhaust gas discharged from the main engine (especially the gas turbine) of the ship is extremely hot, and the boundary of the outside water along the hull skin below the surface of the water by heat exchange with the exhaust gas. It is an object of the present invention to provide an apparatus in which the layer is heated to reduce the viscous resistance experienced by the hull.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the hull resistance reducing device of the present invention is configured such that a duct is interposed in the middle of a discharge passage of high-temperature exhaust gas discharged from a main engine of a ship, and the duct is under the water surface. It is arranged along the inner surface of the outer plate to heat the outer plate, and a heat insulating material is applied to the inner wall of the duct and along the outer surface of the hull outer plate heated by the duct during navigation. It is characterized in that a sailing outer plate temperature control means is provided for heating the relatively flowing outside water and reducing the viscous resistance of the hull due to the outside water.
[0005]
The hull resistance mitigation device of the present invention is characterized in that the navigation outer plate temperature control means includes a control system for generating microbubbles by boiling of the outer water along the hull outer plate. .
[0006]
Further, the hull resistance mitigation device of the present invention includes a control system for the navigation outer plate temperature control means to generate a gas film along the hull outer plate by boiling evaporation of the outer water along the hull outer plate. It is characterized by having.
[0007]
In the above-described hull resistance mitigation device of the present invention, the duct interposed in the middle of the exhaust gas discharge flow path in the main engine of the ship is disposed along the hull outer plate below the water surface and passes through the duct. The hull outer plate is heated by the exhaust gas, and the temperature of the hull outer plate follows the hull outer plate via a navigation outer plate temperature control means that receives information such as the ship speed and the outside water temperature. Control is performed to efficiently reduce the viscous resistance of the hull in the boundary layer of the outside water.
[0008]
When the navigation outer plate temperature control means includes a control system for generating microbubbles by boiling the outside water along the hull outer plate, the hull outer plate is covered with the microbubbles. As a result, the viscous resistance received by the hull is accurately reduced.
[0009]
Further, the navigation outer plate temperature control means includes a control system for generating a gas film along the hull outer plate by vigorous boiling evaporation of outer water along the hull outer plate, and further comprising the hull outer plate. If it is configured to be maintained at a high temperature, the gas film along the hull outer plate is maintained in a stable state, and the viscous resistance received by the hull can be efficiently and greatly reduced.
[0010]
Further, the hull resistance reducing device of the present invention is characterized in that the hull outer plate under the water surface also serves as a wall portion on the outside water side of the duct.
[0011]
The hull resistance mitigation device of the present invention has a number of branches for branching the flow of the exhaust gas to the inner surface of the outer water wall of the duct and transferring the heat of the exhaust gas to the hull outer plate. The flow paths are arranged in parallel to each other.
[0012]
As described above, when the hull outer plate also serves as a wall of the outer water of the duct through which the high-temperature exhaust gas is circulated, the heating of the hull outer plate is directly performed by the exhaust gas. It will be significantly improved.
[0013]
A plurality of branch passages that can branch the flow of the exhaust gas and transfer the heat of the exhaust gas to the outer skin of the hull are arranged in parallel to each other on the inner surface of the outer wall of the duct. If so, the heat transfer of the exhaust gas to the hull outer plate is more efficiently performed.
[0014]
The hull resistance mitigation device of the present invention is characterized in that the hull outer plate under the water surface also serves as a wall portion on the outside water side of the duct, and the exhaust gas flows on the inner surface of the wall portion on the outside water side of the duct. A large number of endothermic fins extending in the direction are erected in parallel to each other.
[0015]
In this way, when the hull outer plate that is directly heated by the exhaust gas has a large number of endothermic fins standing in parallel with each other, the exhaust gas can be transferred from the exhaust gas to the hull outer plate without disturbing the flow of the exhaust gas. Heat transfer is efficiently performed through the fins.
[0016]
Further, the hull resistance mitigation device of the present invention is a bow shoulder portion, stern shoulder portion, bow valve fold portion, or bottom bilge portion where the flow of water along the hull outer plate causes separation and turbulence is likely to occur when the ship is sailing. The above-mentioned duct is provided on the inner side of the hull, so that at the high temperature of the exhaust gas passing through the duct, the hull outer plate surface of the bow shoulder portion, stern shoulder portion, bow valve bent portion or bottom bilge portion The viscosity of the water along the line can be reduced, or microbubbles and air films can be generated, which can greatly reduce the hull resistance.
[0017]
Further, the hull resistance mitigation device of the present invention comprises a double bottom portion at the bottom of the ship as the duct, and the outer plate temperature control means during anchoring for maintaining the outer surface temperature of the ship bottom outer shell at the biological adhesion suppression temperature during anchoring. Is featured.
[0018]
As mentioned above, when a double bottom part is formed at the bottom of the ship as a duct that introduces high-temperature exhaust gas from the main engine, adhesion of marine organisms such as oysters and seaweed is prevented, especially during berthing When the outer plate temperature control means at the time of anchoring is provided to keep the outer surface temperature of the ship bottom skin at the organism adhesion suppression temperature, it becomes possible to accurately prevent the attachment of marine organisms to the ship bottom.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a hull schematically showing a hull resistance reducing device as a first embodiment of the present invention, and FIG. 2 is an enlarged view of arrows AA in FIG. 3 is a cross-sectional view, FIG. 3 is a hull side view schematically showing a hull resistance reducing apparatus as a second embodiment of the present invention, FIG. 4 is an enlarged cross-sectional view taken along line BB in FIG. 3, and FIG. The hull side view which shows typically the hull resistance reduction apparatus as 3rd Embodiment of this invention, FIG. 6 is CC arrow expanded sectional view of FIG. 5, FIG. 7 is DD arrow expanded cross section of FIG. FIG. 8 is a sectional view showing a modified example of the duct in each of the above embodiments, FIG. 9 is a sectional view showing another modified example of the duct, and FIG. 10 is a fourth embodiment of the present invention. It is a hull transverse cross-sectional view showing the hull resistance reducing device.
[0020]
First, a first embodiment of the present invention will be described. As shown in FIG. 1, a main engine 2 as a gas turbine is installed inside a ship 1 as a coastal ship, and is driven by the main engine 2. The propulsion unit 5 is configured to be operated by the electric power from the generator 3 via the electric motor 4, and the surplus electric power is stored in the battery 6 and used for lighting in the ship.
[0021]
In this coastal vessel, in particular, the exhaust gas can reduce the viscous resistance received from outside water during navigation of the hull so that the characteristics of the main engine 2 as a gas turbine that reaches 600 ° C can be used. Is planned.
[0022]
That is, as shown in FIGS. 1 and 2, the high temperature exhaust gas introduced from the main engine 2 through the exhaust pipe 7 can heat the hull outer plate (the bottom plate) under the water surface. After being guided to the duct 9 along the inner surface, it is further discharged from the chimney 10 through the secondary exhaust pipe 7a.
[0023]
During the navigation, the heating temperature of the hull outer plate 8 in the duct 9 becomes a temperature (for example, 200 to 300 ° C.) suitable for boiling the external water in contact with the outer plate 8 and generating microbubbles. In addition, a navigation outer plate temperature control means 11 is provided. The control means 11 controls the switching valve 12 for adjusting the branch flow rate to the branch exhaust pipe 7b connected to the exhaust pipe 7 before the duct 9. A control system for generating microbubbles by boiling the outside water along the hull outer plate 8 is performed according to the detection signals from the respective detection sensors of the ship speed, the outer water temperature and the hull outer plate temperature in the duct 9. I have.
[0024]
The duct 9 may be provided as a separate body along the hull outer plate 8. However, in this embodiment, the hull outer plate 8 also serves as a wall portion on the outside water side of the duct 9. The wall portion is provided with a heat insulating material 15.
[0025]
The inside of the duct 9 is configured to include a number of branch pipes 9c extending from a header 9a connected to the exhaust pipe 7 to a header 9b connected to the secondary exhaust pipe 7a. 9c is arrange | positioned so that it may closely_contact | adhere to the inner surface of the hull outer plate | board 8. FIG.
[0026]
The structure of the duct 9 may be such that the hull outer plate 8 is directly heated by the exhaust gas introduced into the duct 9 through the exhaust pipe 7 as shown in FIG. Inside the duct 9, heat absorption fins 13 are welded to the inner surface of the hull outer plate 8 for rectifying the exhaust gas in the duct and improving the heat transfer rate to the hull outer plate 8.
[0027]
Further, as shown in FIG. 9 (cross-sectional view), the duct 9 has a structure of a header 9b connected to the secondary exhaust pipe 7a (see FIG. 1) from the header 9a connected to the exhaust pipe 7. A large number of branch passages 9d leading to (see FIG. 1) may be provided, and the hull outer plate 8 may be used as a part of the wall portion of the flow passage 9d. Since it contacts the inner surface of the plate 8, heat transfer can be improved.
[0028]
In the hull resistance reducing device of the first embodiment described above, the duct 9 interposed in the middle of the exhaust gas discharge passage in the main engine 2 of the ship 1 is disposed along the hull outer plate 8 below the water surface. The hull skin 8 is heated by the high-temperature exhaust gas passing through the duct 9, and at that time, the navigation skin temperature control means 11 that receives information such as the boat speed and the outside water temperature is used for the hull skin 8. The temperature is controlled so as to efficiently reduce the viscous resistance experienced by the hull in the boundary layer of the outside water along the hull skin 8.
[0029]
And since the outer skin temperature control means 11 is provided with the control system for generating a microbubble by the boiling of the outer water along the ship hull outer plate 8, it seems that the hull skin 8 is covered with the said micro bubble. As a result, the viscous resistance received by the hull is accurately reduced.
[0030]
Next, a hull resistance reducing apparatus according to a second embodiment of the present invention will be described. As shown in FIG. 3, the main engine 2 as a gas turbine is also provided inside the ship 1 as a coastal ship as shown in FIG. Is installed, and the propulsion device 5 is configured to operate via the electric motor 4 by the electric power from the generator 3 driven by the main engine 2, and the surplus electric power is stored in the battery 6, It is used for inboard lighting.
[0031]
The exhaust gas is used to reduce the viscous resistance received from the outside water during navigation of the hull so that the characteristics of the main engine 2 as a gas turbine that discharges high-temperature exhaust gas can be used.
[0032]
Further, as shown in FIGS. 3 and 4, the high temperature exhaust gas introduced from the main engine 2 through the exhaust pipe 7 can heat the hull outer plate (boat bottom outer plate) under the water surface. After being guided to the duct 9 along the inner surface, it is further discharged from the chimney 10 through the secondary exhaust pipe 7a. In this second embodiment, the hull skin 8 in the duct 9 particularly during navigation. The outer shell at the time of navigation is set to a temperature (for example, 350 to 450 ° C.) suitable for generating an air film along the outer shell 8 by boiling and evaporating the outer water in contact with the outer shell 8. A temperature control means 11A is provided. That is, the navigation outer plate temperature control means 11A controls the flow rate switching valve 12 that adjusts the branch flow rate to the branch exhaust pipe 7b connected to the exhaust pipe 7 before the duct 9 to control the ship speed and the outside water temperature. And a control system for generating an air film along the outer plate 8 by boiling evaporation of the outer water along the hull outer plate 8 according to detection signals from the respective detection sensors of the hull outer plate temperature in the duct 9. ing.
[0033]
The inside of the duct 9 is configured to include a number of branch pipes 9c from the header 9a connected to the exhaust pipe 7 to the header 9b connected to the secondary exhaust pipe 7a. Although the branch pipe 9c is arranged so as to be in close contact with the inner surface of the hull outer plate 8, the structure of the duct 9 is also shown in FIG. 8 or that shown in FIG. Can be adopted.
[0034]
In the second embodiment described above, the navigation outer plate temperature control means 11A sufficiently heats the hull outer plate 8 under the surface of the water using the high temperature of the exhaust gas of the main engine 2, A control system that covers the outer skin of the hull with an air film by vigorous boiling evaporation of the outer water along the outer surface is maintained, so that the air film along the outer skin of the hull is kept in a stable state. The viscous resistance to be received can be reduced efficiently and significantly.
[0035]
In the second embodiment, as shown in FIG. 4, a part of the exhaust gas is moved from the header 9a of the duct 9 connected to the exhaust pipe 7 to the left and right through the control valve 14 into the ship bottom recess 8a. A means for jetting is provided, and the jet gas becomes a bubble for reducing viscous resistance that covers the outer surface of the hull outer plate 8. The control of the opening and closing of the control valve 14 is controlled by the outer shell temperature control during navigation. It may be performed by means 11A.
[0036]
Next, the hull resistance reducing device according to the third embodiment of the present invention will be described. As shown in FIG. 5, in the case of this embodiment as well, as in the second embodiment, the ship 1 as a coastal ship is shown. A main engine 2 as a gas turbine is installed inside, and the propulsion unit 5 is configured to operate via the electric motor 4 by the electric power from the generator 3 driven by the main engine 2. Electric power is stored in the battery 6 and used for inboard lighting and the like.
[0037]
The exhaust gas is used to reduce the viscous resistance received from outside water during navigation of the hull so that the characteristics of the main engine 2 as a gas turbine that discharges high-temperature exhaust gas can be used.
[0038]
Further, as shown in FIGS. 5 and 6, the high temperature exhaust gas introduced from the main engine 2 through the exhaust pipe 7 can heat the hull outer plate (bottom bottom plate) below the water surface. After being guided to the duct 9 along the inner surface, it is further discharged from the chimney 10 through the secondary exhaust pipe 7a. In the third embodiment, in particular, the bow shoulder portion, stern shoulder portion and Also in the bow valve bent portion, ducts 9A, 9B, and 9E for reducing the viscous resistance by heating the hull outer plate 8 under the surface of the water are provided, and the exhaust pipes 7 are provided in the ducts 9A, 9B, and 9E, respectively. , 7a is supplied with high-temperature exhaust gas through branch pipes 7c, 7d, and 7e branched through distribution control valves 12a, 12b, and 12c.
[0039]
The cross sections of the ducts 9A, 9B, and 9E are configured as shown in FIG. 7, and the wall portion on the outside water side of each of the ducts 9A, 9B, and 9E also serves as the hull outer plate 8, and the wall portion on the inside of the ship. Is provided with a heat insulating material 15a. Further, in each of the ducts 9A, 9B, 9E, the hull outer plate 8 is provided with heat absorption fins 13a that perform heat exchange and rectification.
[0040]
Further, in the duct 9 along the hull outer plate 8 at the bottom of the ship, a number of branch pipes 9c extending from the header 9a connected to the exhaust pipe 7 to the header 9b connected to the secondary exhaust pipe 7a. However, the structure shown in FIG. 8 and FIG. 9 described above may also be adopted for the structure in the duct 9.
[0041]
Further, during navigation, the heating temperature of the hull outer plate 8 in the duct 9 is a temperature suitable for generating a gas film along the outer plate 8 by boiling evaporation of the outer water in contact with the outer plate 8 (for example, 350 to The navigation outer plate temperature control means 11A is provided so as to be 450 ° C., and the navigation outer plate temperature control means 11A is connected to the exhaust pipe 7 in front of the duct 9. Control of the flow rate switching valve 12 for adjusting the branch flow rate to the outside is performed according to the detection signals from the respective detection sensors of the ship speed, the outside water temperature, and the hull outer plate temperature in the duct 9, and the outer water along the hull outer plate 8 is controlled. Is provided with a control system for generating a gas film along the outer plate 8 by evaporating the water.
[0042]
And also about duct 9A, 9B, 9E along a bow shoulder part, a stern shoulder part, and a bow valve curve part, the exhaust-gas inflow amount from the exhaust pipes 7 and 7a can be adjusted, and an outer-plate temperature can be maintained at required high temperature. As described above, navigation outer plate temperature control means 11B, 11C, and 11E for controlling the distribution control valves 12a, 12b, and 12c are provided.
[0043]
In the hull resistance reducing device of the third embodiment described above, the same effects as the hull resistance reducing device of the second embodiment described above can be obtained, and the relative flow of external water along the hull can be separated during navigation. Ducts 9A, 9B, and 9E that reduce viscous resistance are also provided for bow shoulders, stern shoulders, and bow valve bends that are prone to occur, which greatly reduces the viscous resistance received from relative water flow during navigation as a whole ship. It will be possible to increase the ship speed and improve the fuel consumption rate.
[0044]
Next, a hull resistance reducing apparatus according to a fourth embodiment of the present invention will be described. As shown in FIG. 10, exhaust gas from a main engine 2 as a gas turbine mounted on a ship 1 is passed through an exhaust pipe 7. Before being discharged from the chimney 10, it is configured to pass through a duct 9C disposed along the hull outer plate 8 in the bilge part on both sides of the hull and a duct 9D as a gap between the double hull outer plate 8b. And the heat insulating material 15 is given only to the ship inner wall part of each duct 9C, 9D.
A flow rate switching valve 12 is provided between the exhaust pipe 7a and the secondary exhaust pipe 7a for directing the exhaust gas directly from the exhaust pipe 7 to the chimney 10.
[0045]
In this fourth embodiment, during navigation, the hull outer plate 8 in the duct is heated by high-temperature exhaust gas that leads to the ducts 9C and 9D, and the outside water in contact with the outer plate 8 is heated or boiled. On the other hand, while reducing the viscous resistance, marine organisms such as seaweed and oysters are kept for the bottom skin of the ship by maintaining the organism adhesion suppression temperature (70 to 90 ° C) through the exhaust gas through the duct 9D even when the ship is anchored. The anchoring outer-plate temperature control means 11D controls the flow rate switching valve 12 and the exhaust pipe distribution control valve 12d connected to the duct 9D at the bottom of the ship. It is configured with a system.
[0046]
Thus, by providing the hull resistance mitigation device of the fourth embodiment, the hull resistance at the time of cruising is greatly reduced, and adhesion of marine organisms such as oysters and seaweeds at the time of berthing is prevented. As a result, the frictional resistance of the hull during low-speed navigation is reduced and the maintenance of the outer surface of the bottom of the ship is simplified.
[0047]
【The invention's effect】
As described above in detail, according to the hull resistance reducing apparatus of the present invention, the following effects can be obtained.
(1) A duct interposed in the middle of the exhaust gas discharge flow path in the main engine of the ship is disposed along the hull outer plate below the surface of the water, and the high temperature exhaust gas passing through the duct causes the duct outside the hull. When the plate is heated, the temperature of the hull outer plate is changed in the boundary layer of the outer water along the hull outer plate through the navigation outer plate temperature control means that receives information such as the ship speed and the outer water temperature. It is controlled so as to efficiently reduce the viscous resistance.
(2) When the navigation outer plate temperature control means includes a control system for generating microbubbles by boiling the outside water along the hull outer plate, the hull outer plate is covered with the microbubbles. As a result, the viscous resistance of the hull is accurately reduced.
(3) The navigation outer plate temperature control means includes a control system for generating a gas film along the hull outer plate by vigorous boiling evaporation of outer water along the hull outer plate, Further, if it is configured to be maintained at a high temperature, the gas film along the hull outer plate is maintained in a stable state, and the viscous resistance received by the hull can be efficiently and greatly reduced.
(4) When the hull skin serves also as the wall of the outer water of the duct through which the high-temperature exhaust gas circulates, the hull skin is directly heated by the exhaust gas, so the heat transfer efficiency is significantly improved. To come.
(5) A large number of branch passages that can branch the flow of the exhaust gas and transmit the heat of the exhaust gas to the outer skin of the hull are arranged in parallel on the inner surface of the wall on the outside water side of the duct. Then, the heat transfer of the exhaust gas to the hull outer plate is more efficiently performed.
(6) If the hull outer plate that is directly heated by the exhaust gas has a large number of endothermic fins standing in parallel with each other, the heat from the exhaust gas to the hull outer plate is prevented without disturbing the flow of the exhaust gas. Is efficiently transmitted through the fins.
(7) The above ducts are provided inside the bow shoulder, stern shoulder, bow valve fold, or bottom bilge, where the water flow along the hull outer plate is likely to be separated and cause turbulence when the ship is sailing. If the temperature of the exhaust gas passing through the duct is high, the viscosity of water along the hull outer plate surface of the bow shoulder, stern shoulder, bow valve fold, or bottom bilge will be reduced. A film can be generated, which can result in a significant reduction in hull resistance.
(8) If a double bottom part is formed at the bottom of the ship as a duct that introduces high-temperature exhaust gas from the main engine, adhesion of marine organisms such as oysters and seaweed is prevented. When a berthing outer plate temperature control means for maintaining the outer surface temperature of the plate at the biological adhesion suppression temperature is provided, it is possible to accurately prevent the attachment of marine organisms to the ship bottom.
[Brief description of the drawings]
FIG. 1 is a side view of a hull schematically showing a hull resistance reducing apparatus as a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view taken along arrow AA in FIG.
FIG. 3 is a hull side view schematically showing a hull resistance reducing apparatus as a second embodiment of the present invention.
4 is an enlarged cross-sectional view taken along the line B-B in FIG. 3;
FIG. 5 is a hull side view schematically showing a hull resistance reducing device as a third embodiment of the present invention.
6 is an enlarged sectional view taken along the line CC in FIG.
7 is an enlarged sectional view taken along the line DD in FIG.
FIG. 8 is a cross-sectional view showing a modification of the duct in each of the above embodiments.
FIG. 9 is a cross-sectional view showing another modification of the duct.
FIG. 10 is a cross-sectional view of a hull showing a hull resistance reducing device as a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ship 2 Main engine 3 Generator 4 Electric motor 5 Propeller 6 Battery 7 Exhaust pipe 7a Secondary exhaust pipe 7c-7e Branch pipe 8a Ship bottom recessed part 8b Double ship bottom outer plate 9, 9A-9E Ducts 9a, 9b Leading part 9c Branch pipe 9d Branch flow path 10 Chimney 11, 11A to 11E Outboard temperature control means 12 Flow rate switching valve 12a to 12d Distribution control valve 13, 13a Heat absorption fin 14 Control valve 15, 15a Thermal insulation

Claims

A duct is interposed in the middle of the exhaust flow path of the high-temperature exhaust gas discharged from the main engine of the ship, and the duct is disposed along the inner surface of the outer plate to heat the hull outer plate under the water surface. In addition, a heat insulating material is applied to the inner wall of the duct, and the outer water flowing relatively along the outer surface of the hull skin heated by the duct at the time of navigation is heated to A hull resistance reducing device, characterized in that a sailing outer plate temperature control means for reducing viscous resistance is provided.

2. The hull resistance reducing device according to claim 1, wherein the navigation outer plate temperature control means includes a control system for generating microbubbles by boiling of outer water along the hull outer plate. .

2. The navigation outer plate temperature control means comprises a control system for generating a gas film along the hull outer plate by boiling evaporation of outer water along the hull outer plate. The hull resistance reducing device according to claim 1.

The hull resistance reduction device according to any one of claims 1 to 3, wherein the hull outer plate under the water surface also serves as a wall portion on the outer water side of the duct.

A large number of branch flow paths for branching the flow of the exhaust gas and transmitting the heat of the exhaust gas to the hull outer plate are arranged in parallel to each other on the inner surface of the outer water wall of the duct. The hull resistance reducing apparatus according to claim 4, wherein:

5. The hull resistance reducing device according to claim 4, wherein a large number of endothermic fins are erected in parallel to each other on the inner surface of the outer water side wall of the duct along the flow direction of the exhaust gas. .

The hull resistance reducing device according to any one of claims 1 to 6, wherein the duct is provided inside a bow shoulder under a water surface.

The hull resistance reducing device according to any one of claims 1 to 7, wherein the duct is provided inside a stern shoulder portion below the water surface.

The hull resistance reducing apparatus according to any one of claims 1 to 8, wherein the duct is provided inside a bow valve bent portion under the water surface.

The hull resistance reducing device according to any one of claims 1 to 9, wherein the duct is provided inside a ship bottom bilge portion below the water surface.

A double bottom portion is formed on the bottom of the ship as the duct, and a berthing outer plate temperature control means is provided for maintaining the outer surface temperature of the ship slab outer plate at a biofouling suppression temperature during berthing. Item 11. The hull resistance reducing device according to any one of Items 1 to 10.