Theoretical And Experimental Study On The Performance Of A Small Flow Vortex Tube

The vortex tube is a simple mechanical device of refrigeration, which can divide the compressed gas stream into two flows, one hot and one cold. Because it has no moving parts and consists mainly of a simple tube, the vortex tube has been used in many fields. Although studys on a large flow vortex tube in room temperature ranges have been emphasized, yet research on a small vortex tube has still been done very little and almost nothing has been found in the open literatures on vortex tubes in low temperature ranges up to now.The main aim of this thesis is to study the performance of a vortex tube in room and low temperature ranges and to find out the mechanism of the energy separation of the vortex tube, as well as to obtain from the applications of a vortex tube in low temperature ranges.The mechanism of the energy separation of a vortex tube is caused by the unsteady variation of pressure, viscosity stress and heat transfer through the energy equation. Based on the first and second law of thermodynamics, entropy generation theory is applied to establish vortex tube model. The minimal pressure ratio is gained by using this model. It can be stated that the process of energy separation in vortex tube can be described in h-s diagram, giving out a new approach for studying on the Ranque-Hilsch effect.The energy separation phenomena of the vortex tube are simulated numerically by using the code system Fluent6.0. Based on the simulation, a new model was established to understand the mechanism of the temperature separation effect with the cold mass flow fraction in a vortex tube by analogizing it as a heat exchanger. It has...