| China is a big grain producing country,and China's northeast region is one of China's major grain producing areas.At present,when the grain drying operation is carried out in the northeastern part of China,most of the tube-type heat exchangers are used for heating the grain drying tower.This heat exchanger has low heat exchange efficiency and serious energy waste,which can no longer meet the agricultural green of China.The concept of development.Heilongjiang Bayi Agricultural University has independently developed a gas-phase rotary heat exchanger for grain drying.This heat exchanger equipment has realized the development requirements of green agriculture for energy conservation and environmental protection.The equipment has been innovatively introduced into the spiral blade by improving the structure of the rotating shell.The structure solves the problems of uneven heating due to flue gas deposition and low heat exchange efficiency of the conventional heat exchanger.However,although the gas phase rotary heat exchanger improves the heat exchange efficiency to a certain extent,the sealing performance of the heat exchanger is affected by the rotation of the main part of the equipment,and the connection between the rotating shell and the air distribution chamber is The loss of heat energy is the main reason for restricting the further improvement of heat exchange efficiency.This paper takes gas phase rotary heat exchanger test bench as the research platform,combined with far infrared thermal imaging technology to test and simulate the test bench,and through the heat exchanger rotating shell fitting structure The improvement is to reduce the heat energy loss of the heat exchanger,so as to further improve the heat exchange efficiency of the heat exchanger.(1)According to the design structure and working principle of the gas phase rotary heat exchanger,a gas phase rotary heat exchanger test bench is built,and the experimental gas phase rotary heat exchanger is studied by using the experimental research method,and the FLIR T420 far infrared thermal imager is utilized.The thermal spectrum of the heat exchanger shell was taken.The experiment showed that the FLIR T420 far infrared camera can capture the temperature distribution of the outer wall of the gas phase rotating heat exchanger and record and display it in the form of a thermogram.(2)Using the image processing function in MATLAB software to program,analyze theisotherm diagram of the heat spectrum of the heat exchanger shell,the three-dimensional map of temperature distribution and the temperature of each point of the shell through the analysis program,and draw the temperature curve of the shell.The analysis of each of the above figures shows that the shell of the gas phase rotating heat exchanger has the highest temperature at the joint of the rotating shell and the air distribution chamber,and the sealing performance and heat preservation performance of other parts are good;the test speed of the heat exchanger test bench is 20r/min.The operation is relatively stable.(3)Using the principle and method of CFD numerical simulation,the numerical simulation and analysis of the two different connection forms of the airflow distribution chamber in the rotating shell and the airflow distribution chamber in the rotating shell are carried out respectively,and the fluids in the two connection modes are adopted.The numerical simulation analysis of the velocity field,pressure field and fluid loss explores the effect of two different connection forms on the leakage.The simulation results show that the different connection forms at the joint have a great influence on the leakage of shell gas,and the loss of the two structures is 12.55%.(4)When the flue gas temperature is set to 100 °C,the shell rotation speed is 20 r/min,and the flue gas and cold air inlet wind speed is 4 m/s,the above two different joint structures are tested and verified.The results show that: in the rotary heat transfer When the operation of the hot flue gas inlet is relatively stable,when the connection form of the hot flue gas inlet portion is embedded in the rotating shell structure,the temperature at the junction of the heat exchanger air distribution chamber and the rotating shell is relatively low,and the connection manner is known.The smaller amount of thermal energy loss is more conducive to further improvement of the heat exchange efficiency of the heat exchanger.The mechanical vibration frequency and amplitude of the gas phase rotary heat exchanger shell at different speeds were measured by experiments.It was verified that the gas phase rotary heat exchanger had the most stable operation at the rotor speed of 20r/min and had the least impact on thermal energy loss.Through the above research,the leakage of flue gas in the chisel structure of the gas phase rotating heat exchanger is reduced,and the heat exchange efficiency of the gas phase rotating heat exchanger is further improved. |
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