JPS5875689A - Heat exchanger for cooling mist - Google Patents

Abstract

PURPOSE:To secure a high heat-transmitting efficiency and contrive to reduce pump power required, by a method wherein grooved finned pipes suitable for a large mist amount are provided on the upstream side of a group of heat-transmitting pipe through which a heat-transmitting medium exchanging heat with a flow of a mist is passed, and grooved pipes suitable for a small mist amount are provided on the downstream side of the group of the heat-transmitting pipes. CONSTITUTION:The heat-transmitting medium such as the vapor of a refrigerant flows through each of the pipes in heat-transmitting pipe groups 5, 6, while gas flow is passed in the exterior of the pipes from inlets 1 toward an outlet 2 as indicated by arrows. The gas flow is generated by a blower 12, water is sprayed from nozzles 9 to be mixed into the gas flows as a mist, and the mist-containing gas flow is directed to the pipe group 5. A large amount of the mist collides with the grooved finned pipes 7 in the pipe group 5 located on the upstream side with respect to the gas flow, and wets the fin surfaces of the finned pipes 7 to enhance cooling efficiency. On the other hand, a small amount of the mist reaches the grooved pipes 8 in the pipe group 6 located on the downstream side with respect the gas flow, and wets the surfaces of the heat-transmitting pipes to enhance the cooling efficiency through evaporation of water films. Most of the mist in the gas flow is condensed by the time the heat-transmitting medium flow out from the pipe groups 5, 6.

Description

Detailed Description of the Invention The present invention relates to a mist cooling heat exchanger that exchanges heat between a mist airflow flowing outside the tube and a heat medium flowing inside the tube, particularly various condensers in which the heat medium inside the U is condensed, and for use in geothermal power generation plants. #Relating to a mist cooling heat exchanger suitable as a condenser. Conventional mist cooling heat exchangers of this type have heat transfer tubes such as smooth tubes or finned tubes arranged in a grid or staggered pattern in the mist air flow passage, and spray nozzles that generate mist are placed in the upstream or downstream portion. It has a structure in which a blower is installed.

The mist cooling method aims to improve cooling performance by colliding ejected mist water with the surface of the heat transfer tube to promote evaporation of the water film. Therefore, in order to promote the wettability of smooth tubes and finned tubes, by forming fine grooves on the -up surface and the fin side surfaces, the capillary and u-force of water in the grooves can be used to thin the heat exchanger tubes. The resulting water film is spread over the heat transfer surface to improve wettability and improve cooling performance.

In such a conventional heat exchanger, the mist generated by the nozzle collides with the most upstream side (first row).
The amount of mist reaching the heat exchanger tubes in the rear row downstream from the third row is reduced. Therefore, as the heat transfer tubes in the rear row move downstream, the dry surface on which no water film exists spreads on the heat transfer surface, and the cooling performance deteriorates.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mist cooling heat exchanger with high heat transfer performance in view of the problems of the prior art described above.

In the present invention, a large amount of mist water exists on the upstream side of the mist in the pre-heat transfer group. This will improve the wettability of the heat transfer surface, and by arranging heat transfer tubes with a wide wetted area, the heat transfer surface will not be chipped even if there is a small amount of mist water on the downstream side or even if the mist hardly reaches the downstream side. A high-performance heat exchanger can be obtained by arranging the heat transfer front with good heat transfer properties.

In the present invention, the groover for forming grooves on the circular tube is capable of forming relatively deep grooves, so that the entire heat transfer surface can be wetted with a small amount of mist i.

Since there are no fins, the electric pitch can be narrowed and many heat transfer tubes can be arranged. In addition, with round grooved rain pipes, deep grooves cannot be made because the fins have grooves, but if there is a large amount of misalignment, the fin sides will be well wetted and the heat transfer area will be reduced. Because it is vastly larger than the inner shrine, high cooling performance is maintained.

Embodiments of the present invention are shown in FIGS. 1 to 6 as tubes and pipes that combine such high-performance heat exchanger tubes.

1 and 2 show the first real @ column.

In a duct 4 having an inlet 1, an outlet 2, and a water receiver 3, an upstream heat transfer/U group 5 and a downstream heat transfer tube group 6 are arranged. The heat exchanger tube group 5 is a grooved fin tube 7 which is often used in the case of a mist electric current with a relatively large number of electric currents. The heat transfer front group 6 is a grooved tube 8 that can be easily detected even by a small amount of mistake.

The nozzle 9 is arranged at the inlet 1 of the duct 4 and injects water toward the heat exchanger tube 'Ins.

A glo and a pump 11 are connected to the nozzle 9, and the water receiver pumps water from the section 3. The water receiver is separately replenished when the amount of water in section 3 becomes low.

The blower 12 is installed at the outlet 2 of the duct 4 (or on the upstream side of the heat exchanger tube group 5), and causes air to flow from the inlet 1 to the outlet 2.

Next, the operation of this embodiment will be explained. Heat transfer: Inside the 9th group 5°6, a heat medium such as refrigerant vapor flows, and airflow outside the building flows from the inlet 1 to the outlet 2 as shown by the arrow. The airflow is generated by a blower 12.

Water is injected from the nozzle 9, becomes mist in the airflow, mixes, and flows into the heat transfer/9 group 5.

The mist wets the surface of the tube fins of the grooved fin tubes 7 of the heat transfer tube group 5 located on the upstream side of the airflow, thereby improving cooling performance. In addition, a small amount of mist reaches the grooved f8 of the heat transfer front group 6 located on the downstream side of the airflow, wets the transfer pA 6 surface, and improves the cooling performance by evaporation of the water film. Most of the mist mixed in the airflow has been condensed by the time the heat medium leaves the heat transfer rit group 5.6.

Figure 3 shows the second fruit of Hon-A Ming, which shows the whole row of cheeks.

When the mist air flow reaches a high speed, the mist captured by the upstream heat transfer group 5 does not fall onto the lower stage of the heat transfer group 6 on the downstream side, but instead falls onto the lower stage of the heat transfer group 6 on the downstream side. falls before the heat transfer. Therefore, there is also a mistake in heat transfer a in this part)
will increase. At this time, upper fi 114 is also applied to the lower heat exchanger tubes of the downstream heat exchanger tube group 6! A grooved fin tube 7 that swims with the heat transfer port group 5 of I is arranged.

FIG. 4 shows the third real row of the present invention. In this implementation row, a heat transfer front group 13 made up of heat transfer tubes effective for forced air cooling is arranged behind the FA group 5.6. Since there is almost no mist in this area, we installed a smooth high-fin pipe 14 to improve the cooling performance and make effective use of the space, as well as stop spraying the mist.
When this heat exchanger is used only for cooling air, this heat transfer tube group 13 is advantageous in improving cooling performance.

FIG. 5 shows a fourth embodiment of the invention. This example is a combination of the second embodiment shown in FIG. 3 and the third embodiment shown in FIG. be able to.

FIG. 6 shows an embodiment of J5 of the present invention. This row is the third implementation row shown in FIG. 4, in which a heat transfer tube group 13 for forced air cooling consisting of smooth high fins 1t14 placed on the most agile side is installed in front of the nozzle 9 at the entrance 1 of the duct 4. be. The airflow guided to the inlet 1 by the blower exchanges heat with the heat exchanger tubes in each row, and its temperature is sequentially lowered. At that time, when cooling is performed only by a simple air flow, the larger the difference in the difference between the surface temperature of the heat exchanger tube and the temperature of the '3A flow, the better, so the cooling performance is improved by doing as shown in FIG. 6.

In the embodiments shown in FIGS. 1 to 6 above, the number of rows of heat exchanger tubes, each having independent characteristics, is not limited to what is shown in the figures, and the number of rows of heat exchanger tubes that are sprayed from the nozzle, the temperature of the heat exchanger tubes, It is decided as appropriate depending on the arrangement pitch of the heat exchanger and heat transfer tubes, etc.

As explained above, according to the present invention, a heat exchanger with high heat transfer performance can be obtained, and the power of the mist/water circulation pump can be reduced by promoting evaporative heat transfer of mist water. be able to.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a first embodiment of the mist cooling heat exchanger of the present invention, FIG. 2 is an enlarged first section view of the lower part of FIG. 1,
FIGS. 3 to 6 are enlarged sectional views of main parts showing other embodiments of the mist cooling and instant heat exchanger of the present invention. 1...Inlet, 2...Outlet, 3...Water tray, 4...
...Duct, 5.6.13... Heat exchanger tube group, 7... Grooved fin tube, 8... Grooved tube, 14... Smooth high fin tube, 9... Nozzle. Patent applicant: Makoto Ishiita, director of Eka Institute of Technology - Fig. 1, fl z Fig. 3

Claims (1)

[Claims] 1. In a mist cooling heat exchanger that flows a mist airflow containing fine water droplets in a cooling airflow outside the tube and exchanges heat with a heat medium flowing inside the tube, at least 10,000 fins are provided on the upstream side of the mist airflow. A group of heat transfer elements consisting of grooved fin tubes with fine grooves on the surface of the tube is arranged, and on the downstream side there is a
A mist cooling heat exchanger characterized in that a heat transfer tube group consisting of grooved tubes provided with I is arranged.