Research On Influence Of Fluid Flow And Heat Transfer Performances For Heat Transfer Vertical Upward Pipe Interpolated Helix

The heat exchange tube interpolation spiral technology is widely used in engineering,although this technology can increase the heat transfer coefficient of the vertical upward pipe,but increase the flow resistance.In order to be able to fully understand the influence of the parameters of the interpolated spiral(e?D?and p)on the flow field and heat transfer.This paper will develop the helical reciprocating analysis,Fluent numerical simulation,PIV experiment and heat transfer experiment.The content of this paper is as follows:Firstly,it is analyzed of the research status of heat transfer technology and flow field visualization of the interposer,and proposed the research problem of the flow field and heat transfer performance of the vertical upward pipe interpolation spiral.The relationship between the helical structure parameters and the helical axial velocity is analyzed by interpolation spiral reciprocity.The relationship between the helical structure parameters and the axial wave velocity is closely.Through the cold film interpolation spiral experiment,it is found that the reciprocating periodic motion can be performed only relying on the impact of its own fluid.The experimental data obtained provide the basis for numerical simulation.Secondly,using Fluent to numerically simulate the flow field in an inserted spiral vertical upward pipe.Analyze the effect of spiral parameters(e?Dand p)on heat transfer,resistance and pressure drop in the flow field of the tube.The results show that,when Re is the same,compared with the smooth pipe,the interpolated spiral heat transfer tube Nu increases 1.84-2.85 time.Spiral parameters e=1.6 mm,p=20 mm,D=24 mm PEC is greater than 1,with a maximum of 1.25 and a minimum of 1.04.Thirdly,a flow measurement platform for fluid in the PIV pipe is built to analyze the influence of the spiral parameters on the flow field in the pipe.The experimental results are compared with the smooth pipe.The radial velocity of the core region of the interpolation spiral changes in an M-shape,and there is almost no fluctuation in the smooth pipe;The velocity was increased by about 1.19?1.35 times;the fluid vorticity increases,and the disturbance is intense,and the vorticity increases by 1.05 to 1.55 time.Finally,a heat transfer experiment platform is built to analyze the influence of spiral parameters(e=0.8?1.2?1.6 mm,D= 24?27?30 mm andp=10?15?20 mm)on the heat transfer coefficient of the heat exchange tubes.Important orders are p>e>D.Compared to the smooth pipe,when the heat exchange tube inlet Re from 6999 to 17180 optimal combination is p=20 mm,e=1.6 mm and D=24 mm,The optimal pitch,wire diameter,and middle diameter were increased by 40.5%-50.2%,35.8%?40.9%,and 30.3%?33.1%in comparison with empty tubes.Comprehensive numerical simulation,PIV experiment,and heat transfer experimental result show that:Re from 6999 to 17180,the influence of spiral structure parameters on flow field,PEC,and heat transfer performance is p>e>D;with increasing Re,the order of influence is the same,and the optimal spiral structure parameters is p=20 mm,e=1.6 mm,and D=24 mm.