Simulation Analysis of the High-power Thermoelectric Generation System Based on Strong Coupling Mechanism

摘要

In this paper, we investigated a kind of thermoelectric generation with a high power-density structure which takes the form of centralized cooling in the cooling channel and forced convection heat transfer in place of thermal conductivity. By establishing a dynamic model of the thermoelectric power generation system, dynamic circuit and heat transfer characteristics were obtained. Based on analyzing the computer simulation model, simulation algorithm of thermoelectric conversion device, the instantaneous physical characteristics parameters and the method to seek equation coefficients of voltage-current characteristic are all studied easily. As a case of calculation, convection-radiation heat transfer and circuit characteristics of a two kilo watt high power density thermoelectric generator was analyzed by means of dynamic numerical simulation in the condition of pulsating, high-speed, high-temperature flow. So we obtained the flow field and temperature field distribution. And then we investigated the relationship between heat transfer rate, flow velocity, temperature distribution and the change of output. Through simulation analysis, it shows that the strengthening mechanism cannot only increase the heat transfer area effectively, but also improve the loading performance of a thermoelectric power generation system. The ratio of perimeter to diameter in the section of heat exchanger was up to 5.07, and the internal resistance of total circuit system was decreased about 83.2%. The performance of temperature field fluctuates when a thermoelectric generator works with pulsating flow. Despite fluctuations in the value of a little change, the fluctuation of the output voltage is still very strong because of the high sensitivity of the thermocouples. The flow state in the passage of thermoelectric generator is one of the main factors that affect the amount of heat exchange. radiation turns to be a main form of the heat transfer, when the fluid flows at a high speed. Airflow resistance can be obtained by means of changing the shape of cross section in the channel. At the same time, the heat transfer area can be increasing due to the change, and the output power of unit volume will be improved effectively.