1987 Fiscal Year Final Research Report Summary
The development of a distributor for a coolant two-phase flow in a heat pump and an air conditioner
| Project/Area Number |
61850038
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Kyushu University |
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Principal Investigator |
FUKANO Tohru Kyushu University, Professor, 工学部, 教授 (60037968)
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| Co-Investigator(Kenkyū-buntansha) |
渡辺 吉典 三菱重工(株), 技術本部名古屋研究所, 主任
青木 美昭 三菱重工(株), 技術本部名古屋研究所, 主査
KADOGUCHI Katsuhiko Kyushu University, Research associate, 工学部, 助手 (60194867)
AOKI Yoshiaki Mitsubishi Heavy Industries, LTD, Manager
WATANABE Yoshinori Mitsubishi Heavy Industries,LTD, Chief
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| Project Period (FY) |
1986 – 1987
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| Keywords | Distributor / Junction / Coolant two-phase flow / Heat pump |
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| Research Abstract |
The purpose of this investigation is to develop a distributor which can distribute a proper amount of coolant corresponding to the thermal load of branches from a main pipe. It improves the efficiency and the reliability of a heat exchanger. The results are summarized as follows:
(1) Uneven distribution of liquid caused mainly in a while the liquid slug acceleratedlyh flows into the branch since the static pressure at the inlet of the branch decreases with increasing in the liquid column length. This signifies that the liquid flow rate depends on the magnitude and the passing velocity of the liquid slug. This mechanism caused the uneven distribution of liquid flow rate in each branch.
(2) In the case where the fluid distributes verticallyh upward into a Y type branch uneven distribution is caused by the inclination of the pipe line when the flow pattern just upstream of the branch is bubbly flow, because bubbles defleclt to the upside of the pipe due to gravityh and the mixture flows into two branchs with keeping the uneven distribution of void fraction as it is. Even if a special distributor is inserted just upstream of the branches no improvement appears because it breaks bubbles to much smaller size and the uneven distribution inherently caused by a bubbly flow is unchanged.
(3) While the mechanism of the uneven distribution discribed in (1) is still active, the results for R113 show that the uneven distribution is relieved in this case where the branch was heated byu simulating the actual heat exchanger. This is due to the generation of large momentum change of the fluid between the inle and outlet of tghe branch. This signifies that the distribution of the fluid is controlled by the force balance amoung the static pressure, the frictional pressure drop and the momentum change due to evaporation.
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