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

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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.