JPH0447238B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a heat transfer promoting device in a heat exchanger. ) Regarding a heat transfer promoting device used as a power source for an electrode.

(Prior art) An EHD electrode is installed opposite the heat transfer wall, and the electrode causes disturbances such as fluid displacement in the boundary layer near the heat transfer wall, thereby promoting heat transfer. This technique is publicly known. (Refer to Japanese Unexamined Patent Publications No. 62-228895 and No. 62-259396.) The heat transfer accelerator described above will be briefly explained with reference to FIGS. 2 and 3.

FIG. 2 shows a condensing heat transfer accelerator, in which an EHD electrode wire 2 is installed opposite a heat exchange tube 1. A high voltage of 6000V or more is applied to the EHD electrode wire 2. Cooling water is flowing inside the heat exchange tube 1, and surrounding gas condenses and adheres to the surface of the heat exchange tube 1. If this condensed liquid film exists on the surface of the heat exchange tube 1, it will interfere with the condensation of the gas, so it is desirable to remove this liquid film as soon as possible (or reduce the film thickness). A condensation promoting device that utilizes this phenomenon draws the condensate adhering to the surface of the heat exchange tube 1 toward the EHD electrode wire 2 and discharges it. For this reason, the thickness of the liquid film adhering to the surface of the heat exchange tube 1 is always reduced, and condensation is promoted.

Figure 3 shows an EHD electrode used in an evaporative heat transfer device or a convection heat transfer device. An EHD electrode 4 is installed opposite the heat transfer surface 3, and the EHD electrode 4 has a high voltage of 6000V or more. Voltage is applied.
Heat is exchanged between the heat transfer surface 3 and the liquid 5. The high voltage of the EHD electrode 4 generates a flow as shown by arrow P in the figure, which disturbs the boundary layer of the heat transfer surface 3 and promotes heat transfer.

In addition to the heat transfer accelerating device using the EHD electrode described above, there are many other known heat transfer accelerating devices that utilize the EHD phenomenon. Here, the effect that occurs in the liquid due to these EHD phenomena is hereinafter referred to as the EHD effect), and this is used to promote heat transfer.

(Problems to be Solved by the Invention) By the way, the conventional heat transfer accelerator using the EHD effect requires a special power source for the EHD electrode, which causes increased costs and an increase in the size of the heat transfer accelerator. was.

Generally, the power consumed for EHD operation is small, and it cannot help but be said that it is inefficient to install a large power supply device to obtain such a small amount of power.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make the heat transfer promoting device smaller and lighter, and at the same time, to reduce the cost by making the power consumed by the EHD electrode self-sufficient.

(Means for Solving the Problems) The present invention is characterized by arranging an EHD electrode facing the heat transfer surface and applying a high voltage to the EHD electrode, thereby exerting an EHD effect on the fluid near the heat transfer surface. In a heat transfer device designed to promote heat exchange, a thermoelectric generation element is installed on the heat transfer surface, and a DC transformer transforms the electromotive force generated in the thermoelectric generation element into a high voltage. is provided, and the high voltage obtained by the DC transformer is transferred to the EHD.
It is applied to the electrode, thereby
This enables self-sufficiency in the power consumed for EHD action.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of a heat transfer promoting device showing an embodiment of the present invention, in which a low-temperature fluid 12 flowing through one flow path 11 and a high-temperature fluid 14 flowing through the other flow path 13 are shown in FIG. Heat is transferred via a heat transfer wall 15 installed between them.

Inside the flow path 11, facing the heat transfer wall 15,
An EHD electrode 16 is installed. Further, a thermoelectric power generation element 17 is installed on the heat transfer wall 15. This thermoelectric power generation element 17 generates electricity by using the temperature difference between the fluid 12 and the fluid 14, and a transformer 18 is provided to transform the electromotive force obtained by this thermoelectric power generation element 17 into a high voltage. ing. This transformer 18 is a DC transformer, which transforms the electromotive force generated by the thermoelectric generating element 17 into a high voltage, and uses this high voltage as a power source for the EHD electrode 16.

The operation of the present invention configured as above will be explained below.

An electromotive force is generated in the thermoelectric generating element 17 due to the temperature difference between the fluid 12 and the fluid 14, and this electromotive force is transformed into a high voltage by the transformer 18. and,
When this high voltage is applied to the EHD electrode 16, the
Due to the EHD action of the EHD electrode 16, the heat transfer wall 15
A flow as shown by arrow Q occurs near . This flow Q promotes heat transfer.

It should be noted that the present invention is not limited to the embodiment described in FIG. 1, but can be applied to various other heat transfer promoting devices that utilize the EHD effect.

(Effects of the Invention) The effects of the present invention explained above are as follows.

First, since a special power source for the EHD electrode is not required, the heat transfer promoting device using the EHD electrode can be made smaller, lighter, and lower in cost.

It becomes possible to install the heat transfer accelerator in a place where there is no power supply.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a heat transfer accelerator according to an embodiment of the present invention, Fig. 2 is a schematic sectional view of a conventionally known heat transfer accelerator, and Fig. 3 is another conventionally known heat transfer accelerator. FIG. 11: Channel, 12: Fluid, 13: Channel, 14:
Fluid, 15: Heat transfer wall, 16: EHD electrode, 1
7: Thermoelectric power generation element, 18: Transformer.

Claims (1)

[Claims] 1 Place the EHD electrodes facing each other on the heat transfer surface, and
In a heat transfer device that promotes heat exchange by applying a high voltage to an electrode to cause an EHD effect in the fluid near the heat transfer surface, a thermoelectric generating element is installed on the heat transfer surface. , utilizing a thermoelectric element characterized in that a DC transformer is provided to transform the electromotive force generated in the thermoelectric generation element into a high voltage, and the high voltage obtained by the DC transformer is applied to the EHD electrode. heat transfer accelerator.