An Experimental Study And Numerical Simulation Of Heat Transfer On Supercritical Carbon Dioxide In The Horizontal Tube

People have done a lot of work to research the heat transfer properties of supercritical refrigerant, but presently the heat transfer coefficient can not be forecasted precisely and applied to the practices. The convection heat transfer can be different under vary conditions even if the initial pressure and the flow density do not change distinctly for the complexity of the heat transfer of supercritical fluid. The main target of the thesis is shown as follows:Firstly the main factors affecting the heat transfer of supercritical carbon dioxide were concluded and analyzed including initial pressure, mass fluxes, buoyancy lift, and flow density. Specific heat and the change of properties in the flowing boundary layer can be the explanation of the factors affecting the heat transfer of supercritical carbon dioxide.Secondly the testing section was rebuilt under the experimental basis of the former, the flowing way of the cooling water was changed from adverse current to the uprightness flow and the heat transfer was researched again.Thirdly the initial pressure, mass fluxes, cooling water current affected heat transfer under water cooling uprightly, and the buoyancy lift criterion was calculated and proved the measured results can be neglected;Reynolds number, Prandtl number and Nu compared under vary cooling ways;the measured results and the models compared and the equation fitting this experimental condition was found.At last the theoretic research of supercritical carbon dioxide was analyzed and numerical simulation was displayed under certain conditions. As the properties of the supercritical carbon dioxide were changed heavily, the numerical simulation of supercritical carbon dioxide is waiting for the perfect.