JPS61225591A - Method to promote transferring of heat utilizing electric field in heat exchanger - Google Patents

Abstract

PURPOSE:To miniaturize a heat exchanger by shortening the region of a pipe where a flow of atomized fluid is turned into steam, by making a pipe an electrode on one side and by making a mesh electrode the electrode on the other side, and by applying high voltage across both electrodes. CONSTITUTION:A mesh electrode 11 is provided encircling the center of the section of a pipe 1. The pipe 1 itself is an electrode on one side, while the mesh electrode 11 is an electrode on the other side. An electric field is established between the mesh electrode 11 and the pipe 1 when high voltage is applied across them. A gas 3 will gather in the neighborhood 13 of the center of a pipe 1, because an electric field is not established in this region. On the other hand, minute drips 6 tend to gather in the vicinity 4 on the inside wall of a pipe 1. The minute drips 6 will have more chance to contact to the inside wall and more and more they become easy to be evaporated by receiving heat from the outside of a pipe 1. With such an arrangement, the turning speed of injected fluid into steam can be accelerated. Accordingly the length of a pipe 1 can be shortened, as a result, the size of a heat exchanger can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of promoting heat transfer using an electric field in a heat exchanger that transfers heat by boiling a heat medium flowing through a pipe.

(Prior Art) There is a heat exchanger that transfers heat by boiling a heat medium such as fluorocarbon or water flowing through a pipe using heat from outside the pipe.

Referring to FIG. 3, pipe line 1 of this heat exchanger (not shown)
It shows how the heat medium 2 inside the pipe changes when it receives heat Q from the outside of the pipe 1. The heat medium in the liquid 2 state receives the heat Q and boils.

At the beginning of the conduit 1, the gas 3 is generated as bubbles in the liquid 2, resulting in a two-phase flow (region A). In the next stage, the gas 3 flows near the center of the pipe 1, and the liquid 2 becomes an annular flow that flows in the vicinity of the inner wall surface 4 of the pipe 1 (region B). The liquid 2 then becomes a spray stream (region C). Finally, all of the liquid 2 is vaporized and becomes vapor 5 (region D).

After leaving the heat exchanger, this steam-5 is sent to a power generation turbine or the like.

(Problem to be Solved by the Invention) However, in the spray flow in region C in the above state, since the fine droplets 6 are uniformly present throughout the pipe 1, the heat Q from outside the pipe 1 is is difficult to transmit to the fine droplets 6, and it takes time for the DglI region to completely vaporize into vapor. Therefore, the length of the pipe line 1 from the spray flow region C to the steam region D is required to be long, which is one of the causes of hindering miniaturization of the heat exchanger.

An object of the present invention is to shorten the pipe line 1 in the region where the spray flow becomes steam by promoting heat transfer in the spray flow in the C region, thereby downsizing the heat exchanger.

(Means for Solving the Problems) In order to achieve the above object, the present invention promotes heat transfer of the spray stream as follows.

A mesh electrode surrounding the center of the cross section of the pipe is installed at a location in the pipe where the heat medium becomes a spray flow, and the pipe is used as one electrode, and the mesh electrode is used as the other electrode to connect the pipe and the mesh electrode. Apply high voltage to the open circuit.

(effect) The invention works as follows.

When a high voltage is applied between the mesh electrode and the conduit, an electric field is created across the mesh electrode and the conduit. There is no electric field in the mesh electrode, that is, in the center of the conduit 1, and gas collects here. This is because the gas is subjected to a force that causes it to be ejected from an area where the electric field is strong to an area where the electric field is weak.

On the other hand, droplets with a higher dielectric constant than gas are subjected to a force that draws them from an area with a weak electric field to an area with a strong electric field, so the fine droplets gather near the inner wall surface of the conduit. Therefore, the fine droplets receive heat from outside the pipe and are easily vaporized.

(Example) An example of the present invention will be described below based on FIGS. 1 and 2. In the present embodiment, the heat exchanger (not shown) transfers heat by boiling the heat medium flowing through the pipes. FIGS. 1 and 2 show locations in the pipe line 1 where the spray flow conventionally occurs (region C).

In this embodiment, a mesh electrode 1 surrounding the center of the cross section of the conduit 1 is used.
Install 1. Then, the conduit 1 itself is used as one electrode,
A high voltage is applied between the conduit 1 and the mesh electrode 11, using the mesh electrode 11 as the other electrode. 12 is a power source.

An electric field is created between the mesh electrode 11 and the conduit 1. There is no electric field within the mesh electrode 11, that is, near the center 13 of the conduit 1, and the gas 3 gathers here. This is because the gas 3 receives a force that is ejected from a place where the electric field is strong to a place where the electric field is weak.

On the other hand, the fine droplets 6 are attracted near the inner wall surface 4 of the conduit 1 because they are attracted by the stronger electric field.

Therefore, the fine droplets 6 have an increased chance of coming into contact with the inner wall surface, and receive heat from outside the pipe line 1, thereby becoming more likely to vaporize.

In this way, since the spray stream turns into steam more quickly, the length of the pipe line 1 can be shortened, and the heat exchanger can be made smaller.

(Effects of the Invention) As described above, according to the present invention, heat transfer at the stage of spray flow is promoted and the spray becomes steam quickly, so the length of the pipe can be shortened and the heat exchanger can be downsized.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a pipe line of a heat exchanger according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line I-I in FIG. 1. FIG. 3 is a conventional heat exchanger. FIG. 3 is a longitudinal cross-sectional view showing a heat medium in a pipe in the vessel. 1: Pipe line 3: Gas 4: Inner wall surface of the pipe line 6: Fine droplets 11: Mesh electrode C: Point where spray flow occurs

Claims (1)

[Claims] In a heat exchanger that transfers heat by boiling the heat medium flowing through the pipe (1), a central part of the cross section of the pipe (1) is located at a point (C) where the heat medium becomes a spray flow in the pipe (1). A mesh electrode (11) is installed surrounding the duct, with the duct (1) as one electrode and the mesh electrode (11) as the other electrode. Apply voltage to collect the gas (3) near the center (13) of the pipe (1),
A method for promoting heat transfer using an electric field in a heat exchanger, characterized in that fine droplets (6) are collected near the inner wall surface (4) of a pipe (1).