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

本研究的目的是开发一种分配器，该分配器可以根据主管道分支的热负荷分配适当的冷却剂。它提高了热交换器的效率和可靠性。研究结果表明：（1）液柱长度增加，分支入口静压降低，导致液塞加速流入分支，主要是由于液柱长度增加，液塞在短时间内分布不均匀。这意味着液体流速取决于液塞的大小和通过速度。这一机理造成了各分支内液体流量的不均匀分布。(2)在流体垂直向上分配到Y型分支中的情况下，当分支上游的流型为泡状流时，由于气泡由于重力而偏转到管道的上部，并且混合物流入两个分支中，同时保持空隙率的不均匀分布。即使在分支的上游插入特殊的分配器，也不会出现任何改善，因为它将气泡破碎成小得多的尺寸，并且由泡状流固有地引起的不均匀分配没有改变。(3)虽然（1）中描述的不均匀分布的机理仍然有效，但R113的结果表明，在模拟实际换热器加热分支的情况下，不均匀分布得到缓解。这是由于在分支的入口和出口之间的流体产生了大的动量变化。这意味着流体的分布是由力平衡控制的，力平衡除了静压、摩擦压降和由于蒸发引起的动量变化之外。

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.