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The development of a distributor for a coolant two-phase flow in a heat pump and an air conditioner

热泵和空调中冷却剂两相流分配器的开发

基本信息

批准号：
61850038
负责人：
FUKANO Tohru
金额：
$ 2.82万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-61850038/
关键词：
Distributor Junction Coolant two-phase flow Heat pump 二相流合流管

项目摘要

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.

本课题研究的目的是研制一种能从主管道分配与支管热负荷相对应的适量冷却剂的分配器。它提高了换热器的效率和可靠性。结果表明：(1)随着液柱长度的增加，分支入口静压减小，导致液段塞在短时间内加速流入分支，导致液段塞分布不均匀。这表明液体流量取决于液体段塞的大小和通过速度。这一机制导致了各分支中液体流速分布不均匀。(2)当流体垂直向上分布为Y型分支时，当分支的上游流型为气泡流时，由于气泡受重力作用向管道上部偏转，混合液在保持空隙率分布不均匀的情况下流入两个分支，导致管路的倾斜导致分布不均匀。即使在分支的上游插入一个特殊的分配器，也不会出现任何改善，因为它将气泡分解到更小的尺寸，并且由气泡流动固有的不均匀分布不会改变。(3)虽然(1)中描述的不均匀分布机制仍然有效，但R113的结果表明，通过模拟实际换热器加热分支时，不均匀分布得到了缓解。这是由于分支入口和出口之间的流体产生了很大的动量变化。这表明流体的分布是由静压、摩擦压降和蒸发引起的动量变化之间的力平衡控制的。