Stack type heat exchanger

Abstract

The heat exchanger performance of a stack type heat exchanger used as an aircraft engine oil cooler or the like is increased. U-turn type layered hot fluid passages having corrugated fins and U-turn type layered cold fluid passages having corrugated fins are alternately stacked to configure a stacked core. Mixing headers are provided to both side surfaces of the stacked core so as to pass a hot fluid which circulates on a first half side and a return path side through the mixing headers outside of the stacked core. The mixing headers mix the hot fluid which circulates in the inside portion of the U-turn passage and the hot fluid which circulates in the outside portion thereof. The hot fluids are mixed between the plural stacked hot fluid passages. The temperature distribution of the hot fluid in the first half and in the passage width direction is made uniform.

Description

BACKGROUND OF THE INVENTION[0001](1) Field of the Invention[0002]The present invention relates to a heat exchanger suitable for an aircraft engine oil cooler. More specifically, the present invention relates to a stack type heat exchanger in which U-turn type layered hot fluid passages through which a hot fluid circulates and U-turn type layered cold fluid passages through which a cold fluid circulates are alternately stacked.[0003](2) Description of Related Art[0004]In terms of difference between media which cools an engine oil, as aircraft engine oil coolers, two types, that is, a fuel cooled type and an air cooled type, are typical. In addition, in terms of difference in configuration between heat exchangers used, two types, that is, a plate-fin type and a shell-and-tube type, are typical. Used relatively frequently among these combinations is the fuel cooled type oil cooler using the plate-fin type heat exchanger. In the fuel cooled type oil cooler, with cooling of a hot engine ...

AI Technical Summary

Benefits of technology

[0013]An object of the present invention is to provide a stack type heat exchanger which can eliminate the abnormal temperature distribution in the passage width direction of a hot fluid circulating in a U-turn type layered hot fluid passage, and can increase the heat transmission ability, in particular, can significantly increase the cold ability.

[0014]Meanwhile, the present applicant has manufactured the plate-fin type heat exchanger used as the aircraft engine oil cooler which is equipped with the bypass mechanism shown in FIG. 9, more specifically, the counterflow type heat exchanger in which the circulation directions of the engine oil and the fuel are counter. The present inventors have initially considered that the abnormal temperature distribution in the width direction of the hot fluid circulating in the U-turn type layered hot fluid passage 11 is caused by the bypass mechanism, have experimentally manufactured the plate-fin type heat exchanger without the mechanism, and have examined in detail the effect of bypass mechanism on the non uniform oil temperature distribution. Consequently, contrary to expectations of the present inventors, by removing the bypass mechanism, the non-uniformity of the temperature distribution becomes more significant to degrade the heat exchanging performance.

[0015]In other words, in the aircraft engine oil cooler, the bypass mechanism is used only at engine start, is brought into the off state at the time of the typical engine operation, and becomes a header bypass passage which only passes the oil circulating in the first half of the U-turn passage on the hot side through the bypass header 20. At this time, not only the oil circulating in the outside portion of the first half (the portion far from the partitioning member 15 which partitions the first half and the return path of the U-turn passage), but also the oil circulating in the inside portion of the first half (the portion near the partitioning member 15), once pass through the bypass header 20 so that both of the oils are forcibly mixed in the bypass header 20 and then the forcible mixing of the oils is performed in the stacking direction of the U-turn passage on the hot side. The present inventors have considered that such oil mixing in the bypass header 20 causes the abnormal temperature distribution in the passage width direction of the hot fluid circulating in the hot fluid passage 11, but actually, has found to be an effective means for eliminating the abnormal temperature distribution.

Problems solved by technology

Consequently, contrary to expectations of the present inventors, by removing the bypass mechanism, the non-uniformity of the temperature distribution becomes more significant to degrade the heat exchanging performance.

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