JPS63271098A - Counterflow type plate finned heat exchanger - Google Patents

Abstract

PURPOSE:To release a difference of thermal expansion caused by a variation of temperature and to increase the life and reliability of a device by a method wherein a low temperature fluid is flowed in opposition to a high temperature fluid in a space between elements of a heat exchanger in which several elements having a high temperature flow path limited by a pair of plates and a spacer are connected. CONSTITUTION:An element 6 is formed with a high temperature flow passage 5 limited by a pair of plates 1 and spacers 2. Each of the adjoining elements 6 pushes to each other a high temperature gas in an opposite direction and by the same force against uniform hot gas by a flowing-in and a flowing-out of hot temperature gas near both vertical ends 9 and 10 so as to endure the force. Therefore, there is no problem in view of a strength against a gas pressure applied inwardly against a clearance between the elements 6 to which a low temperature gas is flowed, i.e., a central part of a low temperature flow passage even if there is no specific supporting part. Except a junction between the hot temperature gas flowing-in part 9 and the flowing-out part 10, it is possible to endure a gas pressure passing within each of the elements 6 even with a displacement stopper 11 fixed to each of the curved portions 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to regenerative heat exchangers for gas turbines and also to gas heat exchangers.

BACKGROUND ART As shown in Fig. 4, a conventional plate-fin type heat exchanger has a number of layers in which a corrugated fin 02 is sandwiched between two plates 01, and both sides of the corrugated fin 02 are sealed with side pars 03. A heat exchange section is formed by overlapping them. When assembling the heat exchange part, aluminum alloy brazing filler metal (not shown) is clad on both sides of plate 01, and after assembling as shown in the figure, it is heated several times in bow melting salt at about 600"C. When immersed for a minute and heated, the brazing filler metal clad on the plate 01 melts, and then cools to solidify again, and the plate 01, side par 03, and corrugated fins 02 are completely integrated. The joint is very strong, and tensile tests show that it is the base metal that breaks, not the joint.

A header (not shown) that forms a fluid inlet/outlet that separates the high-temperature, high-pressure fluid side and the low-temperature, low-pressure fluid side is joined by welding to the heat exchange section 04 manufactured as described above to form a single panel (Fig. (not shown). One or more panels connected in parallel or series are used as a heat exchanger.

Problems to be Solved by the Invention When such a conventional plate-fin heat exchanger is used as a regenerative heat exchanger for a gas turbine, the combustion exhaust gas inlet temperature is about 550''C and the outlet temperature is about 550''C and combustion. Nitrogen temperature (approximately 20°C and outlet temperature approximately 5°C)
A maximum temperature difference of more than 500"C occurs from the operating condition of 40°C. As can be seen from the above manufacturing process, the entire heat exchanger is connected as one piece, and structurally speaking, there is no expansion or contraction of the component parts. Since this is hardly allowed, the heat exchanger will be subject to extremely large thermal stress unless distortion due to temperature differences can be prevented.

Plate-fin type heat exchangers are commonly used because they can withstand thermal shocks up to a temperature difference of 200"C or more. The current situation is that due to repeated exposure, it cannot withstand thermal shock and has a high risk of being destroyed in a short period of time, making it unusable as a regenerative heat exchanger for gas turbines. .

Means for Solving the Problems In order to solve such conventional problems, the present invention ((
, in a counterflow plate-fin heat exchanger, a plurality of spacers are sandwiched between a pair of plates at appropriate intervals,
These pair of plates and spacers form an element having a limited high temperature side flow path, and a high temperature fluid is allowed to flow through this high temperature side flow path, and a large number of the elements are connected to perform one heat exchange. A low-temperature fluid is made to flow opposite the high-temperature fluid through a flow path on the low-temperature side defined by gaps between these elements.

According to such a means, a high temperature fluid inlet and a high temperature fluid inlet are provided at both ends of an element consisting of a pair of plates having a large aspect ratio in the flow direction of high temperature and low temperature fluids and having at least one bend. Since an outlet is provided and a large number of these elements are connected, flow paths for high temperature fluid to flow in these elements and flow paths for low temperature fluid to flow in the gaps between the elements can be provided, respectively.

EXAMPLE Hereinafter, an example of a single plum tree according to the present invention will be described in detail with reference to FIGS. 1 to 3.

According to the invention, as shown in FIGS. 1 and 2, a plurality of vertically long flat plate spacers 2 are sandwiched between a pair of plates 1 spaced apart by a suitable distance. In addition,
Parallel to this spacer, side pars 3 are fixed to both ends between the plates 1.

The shape of each of the pair of plates and spacers is not a simple flat plate, but in the flow direction of high-temperature and low-temperature fluids, that is, in the regenerative heat exchanger (not shown) of the gas turbine, high-temperature (high! E) gas such as combustion exhaust gas and low-temperature air such as combustion air (
Low 1-E) It has an elongated shape with a large aspect ratio in the gas flow direction, and is provided with at least one 9-shaped curve 4.

In this way, an element 6 having a high temperature side #L path 5 defined by such a pair of plates 1 and spacers 2 is formed. The high-temperature gas is caused to flow from above to below in this high-temperature side flow path.

At the same time, as shown in FIG. 3, one heat exchanger 7 is formed by connecting a large number of elements 6, and a low-temperature side flow path 8 (the first
(see Figure 2), the low temperature gas is made to flow opposite the high temperature gas.

In this case, a hot gas inlet part 9 (upper position) and an outlet part 10 (lower position) are provided near both ends of the pair of plates 1 (or elements 6) in the vertical direction. Then, the plate 1 near both ends
The width of the gap (see Figure 1) is widened outward in this area.

Then, the distance 1] is widened outward and joined only at both ends. Therefore, a gap is generated in the other adjacent portions (center portion) without contact, and the low temperature side flow path 12 is limited by the gap between these elements.

Historically, the elements 6 that have been drilled in this manner connect adjacent elements 6 to their hot gas inlet and outlet portions 9.
] O to be sure ((The panels are connected at random, and the appropriate number of panels are formed.

At this time, a stopper 11 is installed in the horizontal direction along the bend 4 as described above to prevent the elements 6 from becoming unevenly spaced.

One heat exchanger 7 is formed by overlapping and connecting these parts so that the nine parts 4 protrude alternately.

'-1, when viewed as one heat exchanger 7 as a whole, each high temperature gas inlet section 0, and outlet section 9 connected as above, When the panels are assembled (connected) in several stages, these inlet and outlet sections are each treated as one high-temperature gas passage.Then, both ends of this gas passage,
Strictly speaking, the high-temperature gas intake section and outlet section 9 of the outermost element 5 forming the front and rear end outlines of the heat exchanger 7
．． ]0, a high temperature gas inflow pipe (upper position) and an outflow pipe (lower position) 12, ]3 are connected horizontally, respectively.

Apart from these, low-temperature gas inlet pipes or ducts (lower position inlet and outlet pipes (upper position) 14°J5 are installed at both ends of the heat exchanger 70 in the lower direction, respectively) However, in this case, at the joints near both ends of each element 6 in the vertical direction (see Figure 1), the low temperature gas passages (not shown in the figure) are connected in the vertical direction. Along this path, the low temperature gas is forced to flow from below to above in opposition to the flow of the high temperature gas.

Next, its effect will be explained.

Each panelized element 6 has high temperature gas inflow and outflow sections 9 and 10 near both vertical ends of each element 6.
Adjacent elements 6 (plates) are each given equal gas pressure of high temperature gas,
The elements 6 adjacent to each other on the lower side of the high mogas push each other in opposite directions with the same force! It is designed to endure. In this way, each element 6 is joined at both ends, so that the low temperature gas flows in the gap between the elements 6, that is, in the center of the low temperature 11I port flow path 12, in the inward direction ((against the gas pressure applied). In this case, there is no problem in terms of strength even if no supporting portion is provided.

At the same time, except for the joint between the hot gas inlet and outlet parts 9 and 1°, the approximately dogleg-shaped surface of the plate 1 is 9 parts 4.
Also, each element 6 is
It can withstand the gas pressure that passes through it well.

Further, in this bent portion 4, when the plate 1 is exposed to the high temperature of high-temperature gas and the temperature rises and thermal expansion occurs, the bent portion 4, which has an appropriate elasticity, will direct the expansion outward (
By moving (or deforming) in the projecting direction, the object can be released sufficiently and freely. Although the bending portion 4 actually moves slightly, by performing such a movement, the distortion that conventionally occurs in the plate can be suppressed to a very small one, so that each element 6 as a whole It is also possible to almost eliminate the occurrence of thermal stress at both ends of the joint.

On the other hand, if the temperature of the plate falls at the 9th part of this song, the bending part 4 can move inward (in the 9th direction) (or return to its original position) over time, so the iTT-mentioned error will occur. Similarly to the above case, the occurrence of thermal stress can be almost eliminated at both ends of each element 6 in the vertical direction.

Even if a large number of elements 6 having the above-mentioned configuration and function are divided into panels, connected and fixed to form one heat exchanger 11, thermal stress will not be generated in each panel. Since most of the problems have already been resolved at the Niremen 1-6 stage, it is important to make sure to eliminate the occurrence of thermal stress at these fixed parts.

Effects of the Invention As detailed above, according to the present invention, the pair of plates constituting the element of the heat exchanger can freely release the difference in thermal expansion due to temperature changes of the high-temperature fluid or the low-temperature fluid. Therefore, it is possible to reliably eliminate thermal stress at the portions of the heat exchanger that are fixed to the various pipes. Therefore, it is possible to produce a counterflow plate-fin type heat exchanger that hardly causes thermal shock.

This allows it to be used in regenerative heat exchangers for gas turbines with temperature differences of 500"C or more, and also to increase the overall lifespan and reliability of the gas turbine system. is possible.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of essential parts showing an example of a counterflow plate-fin type heat exchanger according to the present invention, Fig. 2 is a cross-sectional view of a part thereof, Fig. 3 is a schematic assembly diagram thereof, and Fig. 4 is a conventional one. 1 is a partial perspective view showing a counterflow plate-fin type heat exchanger of FIG. 1...(pair of embrates, 2...spacer, 5...high temperature side flow path, 6...element, 7...heat exchanger, 8...
Low temperature side flow path. (7 others) Figure 3 Figure 4

Claims (1)

[Claims] A plurality of spacers are sandwiched between a pair of plates spaced at appropriate intervals, and an element having a high-temperature side flow path defined by the pair of plates and the spacers is formed. In addition to flowing the high-temperature fluid, a large number of the elements are connected to form one heat exchanger, and the low-temperature fluid is flowed in opposition to the high-temperature fluid through a low-temperature side flow path defined by gaps between these elements. A counterflow plate-fin type heat exchanger.