Numerical And Experimental Study Of The Flow Resistance And Heat Transfer Performance Inside The Spiral Vortex Tube

With the continuous promotion of the “Double carbon”strategy,we need to continuously optimize the heat transfer process and take the energy-saving,highefficiency and green development path.it is very important for the study of enhanced heat exchanger tubes with simple fabrication and excellent performance.In this paper,a spirally arranged vortex tube is presented,and the flow resistance and heat transfer in the tube are studied by means of experiment and numerical method.Firstly,according to the actual machining process of the vortex tube,the finite element modeling of the vortex tube with different arrangement is carried out by using the Explicit Dynamic method and the agreement between the actual structure and the model of the vortex tube is achieved.Realizable k-ε turbulent model was used to investigate the flow and heat transfer characteristics and the temperature field distribution in staggered-arrangement,aligned-arrangement,spiral-arrangement with spiral angleθ=63° and spiral angle θ=103°.It is found that the flow in the spirally arranged vortex tube can produce the whole spiral flow under the action of the spiral channel,and different spiral angles will induce different degrees of swirl disturbance in the flow field in the tube.θ=63° has the best comprehensive performance,the maximum comprehensive performance factor E is 1.24,which shows that the combination of spiral structure and vortex node structure has better internal flow resistance and heat transfer performance.The effects of the structure parameters(spiral angle θ,punching depth h and axial spacing g)on the flow resistance and heat transfer performance of the spirally arranged vortex tube with better comprehensive performance are further studied,an test stand for flow and heat transfer in spirally arranged vortex tube was built and use explicit dynamic method to build a one-to-one model,the results of Nu and f experiments are 6.6%-16.2%and 7.6%-22.1% different from the simulation results.Respectively,θ=83°,h=6mm and g=8mm have the best comprehensive performance among the structural parameters.Finally,the structural parameters of the spiral vortex section are the same,and change the stamping shape of the vortex section.The numerical simulation method is used to study the performance of spherical,ellipsoidal and cylindrical vortex tubes and the mechanism of heat transfer enhancement is analyzed by using the Field Synergy Principle.The flow field distribution and heat transfer performance of spherical and ellipsoidal vortex tubes is similar,while the heat transfer intensity of cylindrical vortex tubes is about 8.7% higher than that of spherical vortex tubes.The global mean field synergy angles of spherical and ellipsoidal vortex tube is 88.19°-89.08° and 88.10°-88.98°respectively,under the condition of Re=5000-45000,indicating that the cylindrical stamping vortex structure has better heat transfer enhancement effect,but it also brings a lot of resistance loss,and its comprehensive performance is worse than that of the spherical stamping vortex structure.The research results have certain guiding significance for practical engineering application and provide reference for the use of spiral vortex tube heat exchange equipment.