Energy analysis within a vortex tube

• Novel explanation for the temperature difference in a vortex tube.
• Novel exergy analysis within the vortex tube supports the proposed explanation.
• Good agreement of the exergy analysis between current and other research.

The generation of separated cold and hot streams from a single injection in a vortex tube is known as the Ranque effect. Since its invention, several explanations concerning the phenomenon of thermal separation in a vortex tube have been proposed, however there has not been a consensus, due to the complexity of the physical process inside the tube.This paper proposes an explanation for the temperature separation in a vortex tube based on an experimental study focusing on the flow structure and energy analysis inside the tube. Using the measured flow properties inside the tube, the exergy density distribution along the vortex tube was calculated, from which the reasons for the temperature separation were identified. The good agreement of the exergy density analysis with findings from other experimental work supports the validity of the proposed hypothesis.