JPS6026292A - Crossfin type heat exchanger - Google Patents

Abstract

PURPOSE:To reduce a flow drag of heating medium passing through fins and simultaneously to improve a heat exchanging efficiency, by providing fan-like louvers along the streamline of heating medium created around heating tubes arranged in a staggered fashion. CONSTITUTION:A heating medium flowing in the direction A collides with a heating tube 1, flows along a streamline B and is straightened through the upstanding portion 7 of louver 5. A heating medium flowing along the outer surface of louver 5 around the heating tubes arranged in a zigzag fashion is straightened by the upstanding portion outside the lorver 5, as shown with E. The accelerated heating medium merges with another flow at the rear of heating tube 1, progressively collides with the heating tube 1 arranged at the downstream and flows along the streamline B. A heating medium which flows as shown by the streamline B is branched away at an edge 6 into turbulent flows and has its boundary layer reduced under the flow dividing action of fins. The coefficient of boundary film is thus increased. A radiation of heat which spreads from the heating tube 1 in a radial direction is transmitted through the louver 5 as shown by a streamline C, whereby allowing for the uniform distribution of heat over the fins in an efficient manner, without interrupting the flow line of heat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a cross-fin type heat exchanger in which a large number of fins are arranged in parallel, and a large number of heat transfer tubes are passed through and in close contact with the fins, thereby improving heat transfer efficiency and increasing heat transfer efficiency. This relates to a heat exchanger that reduces flow resistance.

A cross-fin type heat exchanger has heat transfer tubes that pass through a large number of fins arranged in parallel, and allows the heat medium flowing inside the heat transfer tubes to flow outside the heat transfer tubes (in the gaps between the fins). It exchanges heat between the two.

In order to improve the heat exchange efficiency in this heat exchanger, it is possible to increase the flow rate of the heat exchange medium flowing through the gaps between the fins, or to increase the film coefficient by causing turbulence. It is being said.

However, increasing the film coefficient in this way increases the flow resistance.

As described above, in a general heat exchanger, there is an inextricable relationship between heat exchange efficiency and flow resistance, and technical issues remain in this area as a heat exchanger.

In the conventional cross-fin heat exchanger, as shown in FIGS. 1 and 2, elongated louvers 2 with fins 3 cut and raised are formed radially around heat transfer tubes 1.

By forming the louver 2 in this way, the heat medium flowing in the direction of the arrow A flows along the arc-shaped streamline B around the heat exchanger tube 1, so this streamline is cut almost at right angles. As a result, as shown in FIG. 2, the streamline B is branched off toward the edge 4 of the louver 2, creating a turbulent flow and increasing the film coefficient.

In addition, C shown in Fig. 2 indicates a heat flow line, and the path through which the heat of the heat transfer tube 1 is conducted to the fins 3 is designed so that the heat radiated from the heat transfer tube 1 is efficiently transferred to the win. There is.

However, as shown in FIG. 3, the flow of the heat medium generates a vortex on the back side of the heat transfer tube 1, and the heat medium stagnates in this part.

This retention of the heat medium does not reduce the film coefficient of this portion of the heat transfer tube 1 and does not contribute to heat transfer.

Furthermore, when such a vortex is generated, flow resistance also increases. In the conventional louver, the problem of the swirling current has not been solved, and the actual situation is that the heat exchange efficiency and flow resistance have not been solved.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a cross-fin type heat exchanger that forms roots to eliminate the above-mentioned vortex flow and solves the problems of thermal efficiency and flow resistance at the same time. It is something to do.

That is, in the present invention, heat transfer tubes are arranged in a 1,000"S shape, fan-shaped louvers are provided along the streamlines of the heat medium generated around the heat transfer tubes, and the flow of the heat medium is rectified by the fan-shaped louvers. This feature eliminates vortices and divides the flow of the heat medium using the edges of the fan-shaped louvers, increasing the film coefficient.

An embodiment of the present invention will be described in detail below. Fourth
In the figure, the heat exchanger tubes 1 are arranged in a staggered manner and pass through the fins 3. A fan-shaped louver 5 is provided along the streamline B of the heat exchanger tube 1 by cutting and raising the fin 3.

This louver 5 is provided in a portion other than the flow direction A of the heat medium, so that the heat medium flows in the direction indicated by the arrow, collides with the heat exchanger tube IK, and flows like a streamline B.

In this embodiment, four louvers 5 are formed along the flow 49B, and the separation of the fins reduces the boundary layer and promotes heat transfer.

FIG. 5 shows an enlarged view of the louver 5 in degrees Celsius, and the streamline B is divided by the edge 6 and flows along the rising edge 7.
rectified by Note that C in the figure is a heat flow line.

The operation of this embodiment having the grooves as described above will be explained below. In FIG. 4, the heat medium is arranged in a staggered manner and flows in the direction indicated by the arrow with respect to the heat exchanger tubes 1. The heat medium that has flowed in this way first collides with the heat exchanger tube 1 and flows like a stream i1B. This flow glB is rectified by the rising portion 7 of the louver 5. On the other hand, in the area surrounding the heat transfer tubes 1 arranged in a staggered manner, the heat medium flowing outside the louvers 5 is rectified at the rising edge portions outside the louvers 5 as shown by arrow E, increasing the flow velocity and thereby causing heat transfer. merge at the rear of g1,
It sequentially collides with the heat exchanger tube 1 located on the downstream side and flows along the streamline B.

In this series of flows, the heat medium flows along the flow 6+B to the rear of the heat exchanger tube j while being rectified by the louver 5.The heat medium flows in the direction of the arrow F due to the flow of the arrow E, which has sped up the flow velocity. It's like being sucked in and going with the flow.

On the other hand, regarding the heat exchange efficiency, as shown in Figure 5, the heat medium flowing along the streamline B is diverted to the edge 6 and flows into a turbulent flow at this part, and the fins are separated. Therefore, the boundary layer coefficient is increased by 4S, which reduces the boundary layer.

Further, the heat dissipated radially from the heat transfer tube 1 is transmitted through the louvers 5 as shown by heat flow lines C, and is efficiently and uniformly conducted to the entire fin without cutting off the heat flow lines.

As described in detail above, according to the cross-fin type heat exchanger of the present invention, the heat exchanger tubes are arranged in a staggered manner (-1) Since the fan-shaped louver buckets are provided around the heat exchanger tubes, the heat medium flowing in and around the heat exchanger is arranged in a staggered manner. The flow was rectified by the louver, and the heat medium was able to flow without creating a vortex flow at the rear of the heat transfer tube.

As a result, due to the mutual effect of rectifying the heat medium and eliminating vortex flow at the rear of the heat transfer tube, even if the flow rate of the heat medium is increased,
Flow resistance does not increase.

On the other hand, the edge of the louver divides the streamline into a turbulent flow,
In addition, by dividing the fins and making the boundary layer smaller, the boundary coefficient is increased, and the heat flow glands are not cut off to ensure that heat is conducted uniformly over the entire fin, thereby increasing heat exchange efficiency. I was able to improve.

In this way, the flow resistance of the heat medium flowing between the fins can be reduced and the heat exchange efficiency can be improved at the same time, resulting in excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a fin plan view of a conventional cross-fin heat exchanger, and FIG. 2 is an enlarged view of the louvers in FIG. 1. This is a view from H. FIG. 3 is an explanatory diagram showing streamlines of the heat medium relative to the heat exchanger tube. FIG. 4 and FIG. 5 are one embodiment/example of the present invention, and FIG.
The figure is a Z-plane view of the fin, and FIG. 5 is an enlarged perspective view of the louver shown in FIG. 4. 1...Heat transfer tube 3...-Fieure 1 5...-Louver 6...Edge 7...Rising part Figure 1 Section 2 Figure 4 Figure 3 Between

Claims (1)

[Claims] A system consisting of a large number of heat transfer fins arranged in parallel, heat transfer tubes penetrating the fins and arranged in a staggered manner, and fan-shaped louvers cut and raised from the fins and installed along the streamlines around the heat transfer tubes. , the louver is provided in a portion other than the gas flow direction with respect to the transmission rA pipe,
A cross-fin heat exchanger characterized in that the gas flow at the mouth of the heat transfer tube is rectified by a louver.