Measurement on temperature change during dynamic suction process of pneumatic ejector

The dynamic suction process of pneumatic ejector is studied when the pressure inside the vacuum tank decreases from atmospheric pressure to extreme vacuum degree. The temperature change is one of the important parameters in the dynamic suction process of pneumatic ejector. In this study, the temperature change is analyzed by experimental approaches. The temperature is measured by the stop method. Firstly, the temperature curve is obtained for a typical ejector circuit. Then experiments are carried out with different types of ejector. After that, the volumes of vacuum tank are variable with a S size tank and a L size tank. A tank stuffed with copper wires is also used in the experiment to analyze the effect of heat transfer enhancement. The experimental results show that temperature change inside the vacuum tank is affected by ejector flow rate characteristics, vacuum tank volume, and stuffing material. By enlarging heat transfer area with copper wires, the isothermal suction process can be established.