JPH035695A - Thermal transmittance improving device with thermo-electric element - Google Patents

Abstract

PURPOSE:To supply a consumption power by itself, make a small-sized device and further make a light-weight device by a method wherein a DC transformer for transforming an electromotive force generated at a thermoelectrical generating element mounted at a thermal transmitting surface into a high voltage is provided and the produced high voltage is applied to an EHD (electrical hydraulic dynamic) electrode. CONSTITUTION:Heat is transmitted through a heat transmitting wall 15 mounted between a low temperature fluid 12 flowing in a flow passage 11 and a high temperature fluid 14 flowing in the other flow passage 13. An EHD electrode 16 is mounted within the flow passage 11 and a thermoelectrical generating element 17 is mounted in a wall 15. An electromotive force is generated by a temperature difference between fluid 12 and fluid 14. This electromotive force is converted into a high voltage by a transformer 18. As this high voltage is applied to the electrode 16, a flow indicated by an arrow Q is generated near the wall 15 under an action of EHD, resulting in that a thermal transmittance can be promoted. Accordingly, a saving of a special power supply for EHD electrode enables the device to be small in size and light in weight as well as to reduce its cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat transfer accelerator 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 promotes heat transfer without creating disturbances such as fluid displacement in the boundary layer near the heat transfer wall. This technique is publicly known. (JP-A-62-228895, JP-A-62-228895, JP-A-62-228895,
(See Japanese Patent Publication No. 259396) The above heat transfer promoting device will be briefly explained with reference to FIGS. 2 and 3.

FIG. 2 shows a condensing heat transfer accelerator, in which two EHD electrodes are placed facing the heat exchange tube 1. The EHD
A high voltage of 6000V or more is applied to the electrode wire 2. Cooling water is flowing through the heat exchange tube 1, and surrounding gas condenses and adheres to the surface of the heat exchange tube 1. If the 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 (or reduce the film thickness) as soon as possible.
In the condensation accelerator using this EHD phenomenon, the heat exchange tube 1
The condensate adhering to the surface of the electrode is drawn toward the EHD electrode #X2 side and discharged. 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, with the EHD electrode facing the heat transfer surface 3.
A HD electrode 4 is installed, and the EHD electrode 4 has a
A high voltage of V or higher is applied. Heat transfer surface 3 and liquid 5
Heat is exchanged through the opening. The high voltage of the EHD electrode 4 generates a flow as shown by the 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 promoting device using the EHD electrode described above, there are many other known heat transfer promoting devices that utilize the EHD phenomenon. , the action that occurs in the liquid due to these EHD phenomena is hereinafter referred to as the EHD action), and this is used to promote heat transfer.

(Problems to be Solved by the Invention) However, the conventional heat transfer accelerator using the EHD effect requires a special power source for the EHD electrode, which causes an increase in cost and an increase in the size of the heat transfer accelerator. It had become.

Generally, the power consumed for EHD action is small;
It cannot help but be said that installing a large power supply device to obtain such a small amount of power is inefficient.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to reduce the size and weight of a heat transfer accelerator, and at the same time reduce costs, by self-sufficiency in the power consumed by the EHD electrode.

(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 to exert an EHD effect on the fluid near the heat transfer surface. In a heat transfer device that promotes 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 to a high voltage. is provided, and the high voltage obtained by the DC transformer is transferred to the EH
It is located at the point where it is applied to the D electrode, thereby E H0
The power consumed for its operation can be self-sufficient.

(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 is shown.
Heat is transferred through a heat transfer wall 15 installed between the high-temperature fluid 14 flowing in the other channel 13 and the high-temperature fluid 14 flowing in the other channel 13 .

An EHD electrode 16 is installed inside the flow path 11 facing the heat transfer wall 15 . Further, a thermoelectric power generation element 17 is installed on the heat transfer wall 15.

This thermoelectric power generation element 17 generates electricity by utilizing the temperature difference between the fluid 12 and the fluid 14.
A transformer 18 that transforms the electromotive force obtained by
is provided and ν.

This transformer 18 is a DC transformer, which transforms the electromotive force generated by the thermoelectric generator cord 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. When this high voltage is applied to the EHD electrode 16, a flow as shown by arrow Q is generated near the heat transfer wall 15 due to the EHD action of the EHD electrode 16. This flow Q promotes heat transfer.

It should be noted that the present invention is not limited to the embodiment described in FIG.

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

First, it does not require a special power source for the EHD electrode.
A heat transfer promoting device using an 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 17: Thermoelectric power generation element 18: Transformer

Claims (1)

[Claims] By installing an EHD electrode facing the heat transfer surface and applying a high voltage to the EHD electrode, EHD is applied to the fluid near the heat transfer surface.
In a heat transfer device that promotes heat exchange, a thermoelectric generation element is installed on the heat transfer surface, and a direct current transformer that transforms the electromotive force generated in the thermoelectric generation element into a high voltage. A heat transfer promoting device using a thermoelectric element, characterized in that a high voltage obtained by the DC transformer is provided to the EHD electrode.