Analysis And Optimization Of Heat Transfer Based On Principle Of Minimum Entropy Generation And Minimum Thermal Resistance

Heat transfer processes exist extensively in nature and industrial production. In the field of micro-electronics design and application, heat is generated in a tiny geometric structure, and the heat quantity generated per unit volume is huge. High-efficiency heat dissipation mode is needed to ensure the components are in safe temperature. In the field of spacecraft design, how to remove the heat produced by the instrument and equipment in the spacecraft promptly is an important subject in research of spacecraft thermal control system at present. Furthermore, the problems of energy and environment in our country are not positive. The fossil energy reserves are abundant but average personal availability is far below the world’s average. With the exhaust emission by fossil fuel combustion, the contents of the solid particulate matter, nitrogen oxides and oxysulfide in the air are in a high level which leads to bad air quality. To recycle and reutilize the industrial residual heat is one of the ways solving energy and environmental problems.In this paper, heat transfer process was optimized based on the principle of minimum entropy generation and minimum entranspy dissipation thermal resistance to reduce the system mean temperature on the volume to point conduction problem and obtain higher efficiency in industrial waste heat recovery. The main work includes:1. A novel thermal conductivity discretization algorithm was proposed about volume to point conduction problem in high thermal conductivity material filling process. In a rectangular model and both in the radiation boundary condition and the constant surface temperature boundary condition, first continuous layout of high thermal conductivity was calculated iteratively. Then certain quantities of subdomains were divided according to the continuous layout of high thermal conductivity. The high thermal conductivity material filling process was finished by calculating the materials’quantities and places in each subdomain2. In the optimization process of cement rotary kiln heat collector, heat transfer and flow calculation methods as well as further derivation of entropy generation and entranspy dissipation were derived based on experiential formulas. Entropy generation and effectiveness multi-objective optimization was proposed because of the disadvantage of entropy generation optimization. The running conditions of cement rotary kiln heat collector were optimized based on both principles. In terms of optimal conditions, the functional relationship between optimization objective and each condition is researched by keeping two of the running conditions invariant and changing the other condition.3. The network of heat collectors was optimized on the basis of individual heat collector running condition optimization. Different schemes were proposed and optimized that obtained optimal flow distribution in each branch. The optimal scheme was found out by comparing different schemes optimization results.4. Both principle of minimum entropy generation and minimum entranspy dissipation thermal resistance were utilized on the problems of volume to point conduction and heat recovery of heat collectors. The advantages and applicable conditions were investigated by comparing optimization results of two optimization principle.