Abstract: Thermodynamic model for discharge from a tank is presented, and the heat exchange coefficients are determined based on criteria relationship of nature-convection heat transfer and discharge pressure curve of a solenoid with known flow rate characteristics. The discharge process of another solenoid valve with known flow rate characteristics are simulated with the model. It can be seen that the simulation result of model based on natural convection is very close to that of the experiment, which indicates that the model can better express the real discharge process. Then the known heat-exchange model is applied to identifying the flow rate characteristics of discharge solenoids, and the results illustrate this method can conveniently and accurately test the flow rate characteristics of solenoid.

Key words: Flow rate characteristics, Heat exchange coefficient, Natural convection, Thermodynamic model