| Chinese cooking stove is one of the main cooking equipment in China's catering industry,whose outputs are more than tens thousands every year.However,it has low thermal efficiency and high pollutants in exhaust gas due to the relatively simple design and process.In order to solve these problems,a Chinese cooking stove with high thermal efficiency and low pollution was developed,with scheme including premix-combustion with fixed air-fuel ratio,enhanced radiation heat transfer in furnace,exhaust gas waste heat recycle and so on.The energy saving potential of Chinese cooking stoves was analyzed theoretically at first,followed by the influence of excess air coefficient and premixed air temperature on thermal efficiency explored,and the promoting effect of optimizing the furnace structure and using large surface emissivity materials on enhancing the radiant heat transfer in the furnace was analyzed.Furthermore,on the basis of theoretical analysis,the designs including full premixed combustion with constant air-fuel ratio,enhance of furnace radiation heat transfer,recycle of exhaust gas waste heat," burning without gas prevention ",electric control system were presented.According to these ideas,the constant air-fuel ratio of excess air coefficient valve,stepless speed regulation blowers with premixed cavity or not were chosen.A full premixed burner with porous plate,porous ceramic plate installed in central chamber of the furnace was designed with the "burning without gas prevention",electric control system presented.Meanwhile,considering that the fully premixed burner was the most important part in the design of cookWare,theoretical suggestions was provided for the determination of its structural parameters through numerical simulation,and its flame stabilization mechanism and working safety were analyzed under specific structural parameters.The full premixed cooker range was made of rectifier,full premixed burner and shell.The purpose of the rectifier was evenly into the burner fire hole gas velocity,preventing local flamelifting or tempering.The airflow field was simulated while the diameter of rectifier nozzle were 5mm,8mm,and 10 mm,and it could be confirmed that the performance of the rectifier was best while the diameter of rectifier nozzle was 10 mm.The full premixed burner was designed by means of the porous metal palte,and its diameter of fire hole was 2mm.The combustion was simulated while the the number of burner fire hole was 110,150 and 190,and it could be confirmed that the performance of the full premixed burner was best while the number of burner fire hole was 110.Finally,the items were made and the Chinese cooking stove was assembled,the reasonable excess air coefficient,waste heat recovery system of waste heat recovery water flow and exhaust fan speed voltage,and the load regulation ratio of the stove were determined by experimental study,the results showed that: As the heat load was 30 kW,while the excess air coefficient was 1.038,it could reach the state level one energy efficiency standard;while the waste heat recovery water temperature was 16.4?,the flow of recovery of waste heat was confirmed 5kg/min,and the exhaust fan speed voltage was confirmed 1v,and then the efficiency of boiler thermal efficiency,the waste heat recovery and total thermal efficiency was 48.28%,20.79% and 69.07%,the water temperature difference bwtween inlet and outlet was 18.8?,the temperature of exhaust gas was 173.3 ?;In order to suit more cooking environment,the Chinese cooking stove must make sure the load regulation ratio was wide.With the load heat changing from 10.32 kW to 33.04 kW,the Chinese cooking stove worked normally in the load area,and reached the state level one energy efficiency standard,so it could be confirmed that the load regulation ratio of the stove could hit 3:1. |
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