The Investigation Of Influence To Outside Wall Temperature In Pipe When Inlet Temperature Changes

Now, power plants especially the primary air deliver boilers with storage powder manufacturing system usually use indirect pulverized coal concentration measurement based on energy balance theory. This method uses thermistor insert measurement to measure the primary air temperature,pulverized coal temperature and gas-solid mixture temperature. The thermocouple disturbance to flow field and wear and tear of thermocouple problems are ubiquitous when use the thermocouple insert temperature measurement. According to the actual circs, this paper studies the situation if can use the the outside wall temperature measurement to replace thermocouple insert temperature measurement or not. Through numeration, get the relations between the section mean temperature and outside wall temperature, and get the changes of the section mean temperature and outside wall temperature against time when the inlet temperature changes..In the first, this paper builds up the physical model of the primary air pipe, on the basis of actual flow and heat transfer in the pipe, brings forward the hypothesizes and builds up the math model. In the math model standard k-εturbulent model is employed, and this model is checked up by the experimental data.The paper simulates different inlet temperatures of primary air pipe, gets the relation curve of the section mean temperature and outside wall temperature, and also fits the expression. Simulate the primary air pipe when the inlet temperature changes, get the changes of the section mean temperature and outside wall temperature against time.Secondly, this paper builds up the physical model of the gas-solid mixture pipe, on the basis of actual flow and heat transfer in the pipe, uses the particle stochastic trajectory model to numerate. Simulate different inlet flow rate, gets the relation between the inlet flow rate and the particle concentration,the total pressure drop,the particle velocity,the section mean temperature and the outside wall temperature. Get the section mean temperature and the outside wall temperature along the pipe at certain flow rate, and get the changes of the section mean temperature and outside wall temperature against time when the inlet temperature changes.