JPH0297899A - Heat exchanger - Google Patents

Abstract

PURPOSE:To prevent the deterioration of heat transfer performance due to the biased flow of refrigerant by a method wherein a hollow spiral plate, provided with a dam at the end thereof, is inserted into a heat transfer tube positioned at upstream side connected to the inlet port of the inflow tube of a flow distributor. CONSTITUTION:A hollow spiral plate 15, provided with a dam 21 at the end thereof, is inserted into a inflow heat transfer tube 14. According to this constitution, liquid phase B2 among the flows of refrigerant B, flowing through the inflow heat transfer tube 14 and separated into gas phase and liquid phase, is made to flow spirally along the inner surface of the heat transfer tube 14 by the hollow spiral plate 15 to prevent the flow of the same biased to the trough of the spiral part while the gas phase B1 of the refrigerant R is made to flow through the hollow part of the spiral plate 15 to accelerate it. The mixing of the gas phase with the liquid phase B2 on the inner surface of the tube is promoted by the extracting effect of the gas phase B1 accelerated by the dam 21 to restrain the adhesion of the refrigerant B to the wall surface of a branching section 26 and prevent the excessive flow of the liquid phase B2, heavier than the gas phase B1, into a lower outflow tube 24b by the affection of a gravity whereby the uniform distribution of the flow may be effected. On the other hand, the inner surface of the tube is covered at all times by the liquid phase B2, in which boiling heat transfer is generated, whereby the heat transfer coefficient of a heat exchanger may be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat exchanger that distributes refrigerant evenly and prevents deterioration of heat transfer performance due to uneven flow of refrigerant in refrigeration cycles of air conditioners, refrigeration equipment, etc. It is.

BACKGROUND OF THE INVENTION In recent years, the diameter of heat exchanger tubes in heat exchangers has been reduced to meet the demands for higher efficiency and more compact heat exchangers for refrigeration and air conditioning.

As a result, heat exchangers with multiple refrigerant circuits have been adopted, but it is technically possible to divide the refrigerant in the pipes into each circuit without causing it to flow unevenly, and to improve the heat exchange efficiency in each circuit. is important.

Currently, this important shunting role is performed by a three-way bend, which is used as part of a heat exchanger circuit due to its simplicity.

Description will be given below with reference to the drawings.

FIG. 5 shows a heat exchanger with multiple refrigerant circuits.

FIG. 6 shows the shape of the three-way bend used therein, and FIGS. 7 to 8 show the state of the refrigerant inside the heat exchanger tube and the three-way bend when the heat exchanger is continuously operated in the refrigeration cycle.

5 to 8, reference numeral 1 denotes a heat exchanger, which is equipped with a flowing heat exchanger tube 2 and an outflow heat exchanger tube 3. 4 is a three-way bend connecting the flowing heat exchanger tube 2 and the outflow heat exchanger tube 3. Reference numeral 7 denotes heat transfer fins which are pressed against the heat transfer tubes at regular intervals. The three-way bend 4 is composed of a substantially arc-shaped outflow pipe 10 having a substantially right-angled outflow port 9 at both ends, and a substantially straight inflow pipe 11 at a substantially central portion of the outflow pipe 10. The inflow pipe 11 has an inflow port 8 with one end facing in the same direction as the outflow port 9.
, the other end serves as a branch portion 12 to the outflow pipe 10.

The operation of the heat exchanger configured as above will be described below.

The refrigerant A that has flowed into the heat exchanger 1 passes through the heat exchanger tubes 2, becomes a two-phase flow of gas phase A1 and liquid phase A2, flows from the inlet 8 of the three-way bend to the three-way bend 4, and flows through the inlet tube 11. After that, the flow is divided into an upper outflow pipe 10a and a lower outflow pipe 10b at the branching part 12, and the outflow heat exchanger tube 3a passes through the outflow ports 9a and 9b, respectively.
, 3b.

Problems to be Solved by the Invention However, in the above configuration, the refrigerant A separates into two phases, gas and liquid, when flowing through the heat exchanger tube 2, but the ratio of gas and liquid does not become homogeneous and due to the influence of gravity g. The liquid phase A2, which is heavier than the gas phase A1, flows through the lower part of the heat exchanger tube. More three-way bend 4
When the liquid phase A2, which is heavier than the gaseous phase A1, flows into the lower outflow pipe 10b due to gravity g and adhesion to the wall surface of the branching part 12, too much of the liquid phase A2 flows into the lower outflow pipe 10b, causing the refrigerant A to flow into the lower outlet pipe 10b. Equal flow cannot be divided into the heat exchanger tubes 3a and 3b. For this reason, the amount of heat exchanged differs between the circuit sections 1a and 1b of the heat exchanger 1, resulting in a decrease in the heat exchange efficiency, and the difference in temperature of the cooling fluid enveloping the tubes has a negative effect on downstream equipment. had.

In view of the above-mentioned problems, the present invention provides a heat exchanger that can evenly divide refrigerant.

Means for Solving the Problems In order to solve the above problems, the heat exchanger of the present invention has a structure in which a hollow spiral plate having a dam at the end is inserted into the flow tube and the three-way bend inflow tube. It is equipped with the following.

According to the above-described structure, the present invention allows the liquid phase, which tends to flow mostly at the bottom of the heat transfer tube, of the gas-liquid separated refrigerant flowing through the heat transfer tube to be caused to spirally flow along the inner surface of the heat transfer tube using the hollow spiral plate. At the same time, the gas phase is accelerated by flowing into the hollow part of the hollow spiral plate. Furthermore, the extraction effect of the gas phase accelerated at the head of the outlet end promotes gas-liquid mixing with the liquid phase on the inner surface of the tube, suppresses adhesion of the refrigerant to the branch wall, and allows the liquid phase, which is heavier than the gas phase, to This prevents too much water from flowing into the lower outflow pipe and allows for equal flow distribution.

Furthermore, since the inner surface of the tube is always covered with a liquid phase that causes boiling heat transfer with a high heat transfer coefficient, the heat transfer coefficient can be improved.

Example Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 to 3 show the shape of a heat exchanger in an embodiment of the present invention, and Figure 4 shows the state of the refrigerant inside the flow-through heat transfer tube and three-way bend when the heat exchanger is operated in a refrigeration cycle. . In Figures 1 to 4, 13 is a heat exchanger;
It is provided with a floating heat exchanger tube 14 and an outflow heat exchanger tube 16. 1
Reference numeral 7 denotes a three-way bend that connects the flowing heat exchanger tube 14 and the outflow heat exchanger tube 16, and has the same shape as the conventional example. Reference numeral 20 denotes heat transfer fins which are pressed against the heat transfer tubes at regular intervals. A head 2 is provided at the end of the heat transfer tube 14 and the three-way bend 17.
A hollow spiral plate 15 with 1 is inserted. The operation of the heat exchanger configured as above will be described below.

The refrigerant B that has flowed into the heat exchanger 13 passes through the heat exchanger tube 14 and becomes a two-phase flow of gas phase B1 and liquid phase B2, flows into the three-way bend 17 from the inlet 22 of the three-way bend, and flows through the inflow tube 25. After passing through the branch part 26, an upper outflow pipe 24a and a lower outflow pipe 24 are connected.
b, and flow out to the outflow heat exchanger tubes 16a, 16b via the outflow ports 23a, 23b, respectively. At this time, when the refrigerant B flows through the inside of the heat transfer tube 14, it flows through the hollow portion of the hollow spiral plate 15 while increasing the proportion of the gas phase B1 due to heating and evaporation from outside the tube. On the other hand, the liquid phase B2, which tends to flow unevenly at the bottom of the heat exchanger tube 14 due to the influence of gravity, is guided by the hollow spiral plate 15 so as to flow spirally on the inner surface of the heat exchanger tube. Also, a part of the liquid phase B2 is contained in the hollow spiral plate 1.
Due to the effect of the inner edge of No. 5, it is drawn into the high-speed gas phase B1 and flows through the hollow portion in the form of small droplets. In this way, the liquid phase flows at the peripheral opening of the heat transfer tube, and a homogeneous two-phase flow consisting of the gas phase and the liquid phase of small droplets flows at the center, and the liquid phase is prevented from flowing unevenly at the bottom of the tube. Can be done.

In the flow guided in this way, the liquid phase flowing around the inside of the tube is stopped by the outlet end head of the hollow spiral plate, and is blown out from the hollow hole toward the branch part 27 together with the high-speed gas phase flowing in the hollow. , the liquid phase is dispersed into droplets due to the accelerated extraction effect of the gas phase, and the gas and liquid are mixed homogeneously. Therefore, adhesion of the refrigerant B to the wall surface of the branch section 27 is suppressed, and the liquid phase B2, which is heavier than the gas phase B1, flows into the lower outlet pipe 1 due to the influence of gravity.
6b can be prevented from flowing too much to the outflow heat exchanger tube 1.
The divided flows to 6a and 16b can be equally distributed.

Each circuit section 13 of the heat exchanger 13 with equal refrigerant distribution
a and 13b exhibit equivalent heat exchange performance, and can prevent deterioration of heat exchanger performance due to drifting, and can also prevent a large temperature difference from occurring in the tube-enveloped cooling fluid.

Effects of the Invention As described above, the present invention improves heat transfer by uneven flow by installing a hollow spiral plate with a head at the end in the flow-through heat transfer tube and the three-way bend inflow tube to distribute the flow equally to each refrigerant circuit. It is possible to provide a heat exchanger that is highly efficient without deterioration in performance and that does not cause a large temperature difference in the tube jacket cooling fluid in each refrigerant circuit.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of the heat exchanger of the present invention, and FIG.
Figure 3 is a cross-sectional view of the Flowing Heat Transfer Tube and three-way bend in which a hollow spiral plate with a head is installed at the end, Figure 3 is a plan view showing the connection state of the heat exchanger tube and three-way bend in Figure 1, Figure 4 is Fig. 3 is a sectional view showing the flow of refrigerant in the operating state, Fig. 5 is a perspective view showing the general shape of a conventional heat exchanger, Fig. 6 is a perspective view of a three-way bend, and Fig. 7 is the same as Fig. 6. FIG. 8 is a plan view showing the state of piping to the three-way bend heat exchanger, and FIG. 8 is a sectional view showing the flow of refrigerant in the operating state of FIG. 7. 15...Hollow spiral plate, 17...Three-way bend, 2
1...Head. Name of agent: Patent attorney Shigetaka Awano Haka 1 person --- Mute
Father Kai a ・-Inflow C1 Bearing 1 Hollow screw N plate Ichi-ryu Output tube 10000 bends-a Tokyo No. 2 Figure 14...-Flower heat exchanger tube I5 ・-+ti Salt & board +7 1-2 bed E-no-employment notice Figure 1 16-- Outflow heat exchanger tube -... Flow record! 14--Flow λ5 night tube 15--Hollow IN night 17--Mikado 21--Weir section 24...-Outflow pipe...Inflow pipe island--Minute IIf report

Claims (1)

[Claims] 1. A heat exchanger characterized in that a hollow spiral plate having a dam at the end is inserted into a heat transfer tube located on the upstream side connected to an inflow pipe inlet of a flow divider.