Recovering Exhaust Heat Of Combine Harvester Through Heat Pipe Exchanger For Drying Grain

A drying system powered by heat recovered from the exhaust gas of combine harvester using the gravity heat pipe heat exchanger (HPHE) was proposed to improve the fuel efficient of combine harvester. The full-load characteristics of diesel engine were obtained through bench test. The constant heat flux method was used to calculate the heat transfer performances of every heat pipe and then the influence of inlet air parameters at the cold-side of HPHE on the heat transfer process were analyzed by computational fluid dynamics (CFD) simulation under the rated condition (RC) and maximum torque condition (MTC). The results show: for both working conditions, the inlet air velocity has greater effect on the heat transfer performances than the inlet air temperature and the outlet air temperatures are all suitable for the grain drying; the overall heat transfer coefficient of HPHE is higher under RC compared with MTC.