The Method Of Heat Energey Collection And Thimble Heat Exchange In Delivery For Municipal Sewage

This thesis provides theoretical and empirical gist for national patent of invention"City protogenesis sewage cool and heat source direct current deliver heat transfer application method",and optimum design and economic analysis for it. Establish solid foundation in practicable project for this method.The thesis discusses the merit of sewage heat energy collection deliver heat transfer method. Through the metrical dirt roughness height in practicable project, the on-way resistance coefficient formula of sewage pipe is fitted. Through making simulation for experimental findings, coefficient of friction and Nu formula of the fluid in ring space is fitted. The inaccuracy of adopting equivalent diameter method is analyzed. Discuss the influence of caliber ratio on ring space resistance and heat convection. According to the actual project that tests fountain work condition parameters, sewage heat convection coefficient and change law are anti-deduced. Through numerical calculation make the experimental findings fit thimble overall heat transfer coefficient formula. Get additional heat transfer area if considering pipe wall dirt.Adoptingε-NTU method to get single and double passage thimble heat transfer reflux and uniflow heat exchange efficiency formula. Compare the dimension of thimble heat transfer two form efficiency, gaining the unconventional conclusion of more advantageous to heat transfer if adopting uniflow form. Analyze the effective length of thimble practice heat transfer. Get the max and min thimble separation of thimble heat transfer method, providing reference for thimble design.Make ensemble optimization for thimble heat transfer method, getting optimal heat transfer area and optimal heat transfer efficiency in different work condition. Make local optimization for thimble heat transfer method, determining technical feasibility specific flux ratio and velocity ratio range of STDTH system. Present the confirmation method and property of economic specific flux ratio and velocity ratio range. Point the thermosteresis coefficientβrange of double passage STDTH system. Figure out the value of optimal least distance- load ratio DLR. Make economic analysis for thimble heat transfer method, comparing with the heat transfer and running characteristic of shell and tube exchanger. Through the analysis of resistance, establishing pump power expression, getting thimble heat transfer method overall pump power need increase about two doubles. Analyze the consuming material of thimble heat transfer method and common heat exchanger. Through the investigation of market value, establish the economic comparison of filtering surface hydraulic power continuous regenerative system. Through numerical calculation getting if the load - distance ratio LDR >12.6, adopting thimble heat transfer system is more economic.