The Design, Analysis And Experimental Research Of Biomass Fuel Heating Equipment

With the rapid development of Chinese facilities agriculture, as a kind of products which can save energy and protect environment better, the biomass fuel heating equipments are extensively trusted and applied to the greenhouses, vinylhouses, granaries and other places by people.For now, the theoretical analysis of biomass fuel heating equipment is not mature yet, so it is necessary to futher analysis and study its performance. Profited from some domestic and foreign experiences and based on the principles of the combustion, heat transfer and CFD, this paper expounded on the structural design, numerical simulation, experimental research and structure optimization of the device consisted of gasifier, burner and heat exchanger and acquired some practical results. It has important instructive significance to the popularization and application of the device.The biomass fuel heating equipment is supported and promoted by bureau of agriculture machinery in Shanxi province, and is identified by appraisal station of agricultural machinery in Shanxi province. It plays a more and more important role in ensuring seasonal balanced supply of agricultural products, improving qulity of life of urban’s and rural’s residents and improving standards of agricultural mechanization and modernization. In addition, this device has the vital significance to enhance the work efficiency, to reduce the production cost, to enhance the economic efficiency and protect the environment and has a very broad application prospect.The main research results include:1) According to analyzing the characteristics of kinds of gasifiers, the characteristics of biomass gas and the demand of the stability of combustion, the structural characteristics of kinds of tubular heat exchangers and the rule of flow and heat transfer, the author chose respectively updraft gasifier, low pressure and natural wind burner, shell-and-tube heat exchanger suitably used in rural area as the design scheme, then respectively expounded on the structural design of the device consisted of gasifier, burner, and heat exchanger.2) After the experiments on gasifier’s biomass adaptability, the change of gasification etc, on the basis of getting gas components and calorific value, with FLUENT software, the numerical simulation of the main burner was carried out. The results showed that the burner worked well generally, the maximum temperature of the burning chamber was about900K, the flame was stable, the burning chamber could prompt the stability of the flame significantly, and the proportion of the NOx in the exhaust gas was lower. Subsequently, the numerical simulation of the main heat exchanger was carried out with FLUENT software, the author got distribution maps of temperature field and flow field, relevant datas including temperatures and velocities in insets and outsets, capacity of heat transmission and the total heat transfer coefficient,etc in different conditions. The result demonstrated the main heat exchanger worked well, while shell pass had lots of zones the gas could not reach, the local temperature and velocity raised rapidly.3) Subsequently, the experimental research of the prototype of the biomass flue heating equipment was carried out, which proved the exactness of the numerical simulation. The experimental results showed that the gasifier’s biomass adaptability was good, gas components and calorific value varied with air amount and the quality of gas was better. The burner worked well generally, the efficiency of combustion was slightly lower, the formation of NOx met standards and the research results were consistent with the numerical results. The research results of heat exchanger were generally consistent with the numerical results. The variation trend of parameters including temperatures and velocities in insets and outsets, capacity of heat transmission and the total heat transfer coefficient,etc were similar in different conditions.4) The author added deflection baffle to optimize the design proposal on the basis of the model of shell-and-tube heat exchanger, and simulated capabilities of flow and heat transfer to double segmental baffle in different conditions. In the subsequent experiments, the zones the gas could not reach reduced sharply and the area where the local temperature raised rapidly shrinked. Meanwhile outlet temperature of the shell pass, heat transmission, the total heat transfer coefficient and increased observably, and heat transfer was enhanced greatly. The experiments and simulated results demonstrated the rationality and necessity of the optimized model.