Nowadays,people still rely on traditional heating methods in rural areas of northern China,such as Kang(bed-stoves) and burning caves in cold winter.Field measurements of indoor environment were carried out in several...Nowadays,people still rely on traditional heating methods in rural areas of northern China,such as Kang(bed-stoves) and burning caves in cold winter.Field measurements of indoor environment were carried out in several rural houses with burning-cave-coil-Kang coupling heating system in northern China.The results show that this system is able to realize the graded use of internal energy of burning cave.The temperature of supply pipe water ranged from 30 ℃ to 50 ℃ which met the demands in 74.7% of time.The surface temperature of Kang maintained at above 25 ℃.Compared with traditional burning cave,using burning-cave-coil-Kang coupled with heating system has a higher thermal efficiency of 48.9%,which is 8.32% higher than the traditional one.展开更多
The fume bake-out aluminum reduction cell is a novel technology possessing such advantages as easy control for the speed of heating-up, well-distributed temperature, and little cathode and anode oxidation. The key equ...The fume bake-out aluminum reduction cell is a novel technology possessing such advantages as easy control for the speed of heating-up, well-distributed temperature, and little cathode and anode oxidation. The key equipment of fume bake-out is a combustion train whose one important part is a dispensing house. This work deals with the numerical model and the flow and temperature fields of the dispensing house, which suggests that uniformity of flow and energy distribution is influenced by the position, shape and direction of the nozzle and cross dimension of dispensing house mainly, but is less influenced by entry speed. The parameters of the dispensing house structure are optimised to satisfy the requirements for a combustion train in fume bake-out, and appropriate dimensions are obtained for a dispensing house structure.展开更多
Biodiesel （BD） was made from animal-fats reacting with methanol and potassium hydroxide in the laboratory. The biodiesel made in the laboratory was sent to K-petro, the government agency to inspect the quality of an...Biodiesel （BD） was made from animal-fats reacting with methanol and potassium hydroxide in the laboratory. The biodiesel made in the laboratory was sent to K-petro, the government agency to inspect the quality of animal-fats biodiesel, of which generally the quality was acceptable for heating oil for agricultural hot air heater. Kinematic viscosity and calorific values of the biodiesels were measured. BD20（K）, kerosene based biodiesel, showed 18 cSt at -20 ~C. It seems that BD100 can not be suitable for heating fuel under some temperature. As BD content increased calorific value decreased up to 40,000 J/g for 100% BD （BD100） while, light oil calorific value was 45,567 J/g, showing difference of 5,567 J/g （about 12% difference）, Several different fuels including BD20 （biodiesel 20% ＋ light oil 80%）, BD50 （biodiesel 50% ＋ light oil 50%）, BD100 （biodiesel 100%） and light oil were prepared and tested for fuel combustion qualities for agricultural hot air heater and their combustion performances were compared and analyzed. Flame dimensions of biodiesels and light oil were almost same shape at the same combustion condition in the burner of the hot air heater. Generally, CO2 amounts of BDs were greater than light oil, but the differences were so small that it is hard to tell there was significant difference between the BDs combustion and light oil.展开更多
The effects of three factors on combustion performance of petroleum coke, Herin Coal and Shenmu Coal have been studied, including the ratio of primary air, excess air factor, and the swirling intensity of outer second...The effects of three factors on combustion performance of petroleum coke, Herin Coal and Shenmu Coal have been studied, including the ratio of primary air, excess air factor, and the swirling intensity of outer secondary air. The experiments were carried out on a one-dimensional furnace with dual channel swirling burner, in which temperature of center furnace, emission of air pollutants, and burn-out rate of fuel were measured. The results provide the optimal ratio of primary air, excess air factor and swirling intensity of outer secondary air for the fuels. The combustion performance of petroleum coke B is much better than petroleum coke A, but worse than Hejin coal and Shenmu coal. In addition, the burn-out rate of petroleum coke depends much more on the temperature in terminal stage of combustion than in the early stage of combustion.展开更多
Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investig...Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investigated experimentally. The burner consists of two coaxial jets： methane flowing out of the inner, oxidizer from the outer. The flame behavior is studied according to the proportion of oxygen in the oxidizer jet, the oxidizer and the methane jets velocities. The flame is either anchored to the burner, lifted, stationary or not or blown-out. The addition of oxygen produces a decrease of the lift height, a reduction of the length of the reaction zone and an increase in the soot emission. These results have been reported into diagrams of stability where the flame configurations are connected to the competition between the dynamic effect of the injection velocity and the chemical effect of oxygen addition.展开更多
Biogas fuel is a sustainable and renewable fuel produced from anaerobic digestion of organic matter. The biogas fuel is a flammable mixture of methane and carbon dioxide with low to medium calorific values. Biogas is ...Biogas fuel is a sustainable and renewable fuel produced from anaerobic digestion of organic matter. The biogas fuel is a flammable mixture of methane and carbon dioxide with low to medium calorific values. Biogas is an alternative to conventional fossil fuels and can be used for beating, transportation and power generation. CFD （computational fluid dynamic） analysis of the combustion performance and emissions of biogas fuel in gas turbine engines is presented in this study. The main objective of this study is to understand the impact of the variability in the biogas fuel compositions and lower heating values on the combustion process. Natural gas, biogas from anaerobic digester, landfill biogas, and natural gas/biogas mixture fuels combustion were investigated in this study. The CFD results show lower peak flame temperature and CO mole fractions inside the combustor and lower NOx emissions at the combustor exit for the biogas compared to natural gas fuel. The peak flame temperature decreases by 37% for the biogas landfill （COJCH4 = 0.89） and by 22% for the biogas anaerobic digester （CO2/CH4 = 0.54） compared to natural gas fuel combustion. The peak CO mole fraction inside the combustor decreases from 9.8 × 10-2 for natural gas fuel to 2.22 × 10-4 for biogas anaerobic digester and 1.32 × 10-7 for biogas landfill. The average NOx mole fraction at the combustor exit decreases from 1.13 × 10-5 for natural gas fuel to 0.40 × 10-6 for biogas anaerobic digester and 1.06 × 10-6 for biogas landfill. The presence of non-combustible constituents in the biogas reduces the temperature of the flame and consequently the NOx emissions.展开更多
基金National Natural Science Foundation of China(No.21905224)Open funding of National Defence Key Laboratory on Combustion of Explosives(No.6142603200509)。
基金Sponsored by the National Natural Science Foundation of China(Grant No.51178075)the Fundamental Research Funds for the Central Universities(Grant No.DUT17RW118)
文摘Nowadays,people still rely on traditional heating methods in rural areas of northern China,such as Kang(bed-stoves) and burning caves in cold winter.Field measurements of indoor environment were carried out in several rural houses with burning-cave-coil-Kang coupling heating system in northern China.The results show that this system is able to realize the graded use of internal energy of burning cave.The temperature of supply pipe water ranged from 30 ℃ to 50 ℃ which met the demands in 74.7% of time.The surface temperature of Kang maintained at above 25 ℃.Compared with traditional burning cave,using burning-cave-coil-Kang coupled with heating system has a higher thermal efficiency of 48.9%,which is 8.32% higher than the traditional one.
文摘The fume bake-out aluminum reduction cell is a novel technology possessing such advantages as easy control for the speed of heating-up, well-distributed temperature, and little cathode and anode oxidation. The key equipment of fume bake-out is a combustion train whose one important part is a dispensing house. This work deals with the numerical model and the flow and temperature fields of the dispensing house, which suggests that uniformity of flow and energy distribution is influenced by the position, shape and direction of the nozzle and cross dimension of dispensing house mainly, but is less influenced by entry speed. The parameters of the dispensing house structure are optimised to satisfy the requirements for a combustion train in fume bake-out, and appropriate dimensions are obtained for a dispensing house structure.
文摘Biodiesel （BD） was made from animal-fats reacting with methanol and potassium hydroxide in the laboratory. The biodiesel made in the laboratory was sent to K-petro, the government agency to inspect the quality of animal-fats biodiesel, of which generally the quality was acceptable for heating oil for agricultural hot air heater. Kinematic viscosity and calorific values of the biodiesels were measured. BD20（K）, kerosene based biodiesel, showed 18 cSt at -20 ~C. It seems that BD100 can not be suitable for heating fuel under some temperature. As BD content increased calorific value decreased up to 40,000 J/g for 100% BD （BD100） while, light oil calorific value was 45,567 J/g, showing difference of 5,567 J/g （about 12% difference）, Several different fuels including BD20 （biodiesel 20% ＋ light oil 80%）, BD50 （biodiesel 50% ＋ light oil 50%）, BD100 （biodiesel 100%） and light oil were prepared and tested for fuel combustion qualities for agricultural hot air heater and their combustion performances were compared and analyzed. Flame dimensions of biodiesels and light oil were almost same shape at the same combustion condition in the burner of the hot air heater. Generally, CO2 amounts of BDs were greater than light oil, but the differences were so small that it is hard to tell there was significant difference between the BDs combustion and light oil.
基金Acknowledgments This work is supported by Natural Science Foundation of China （NO. 51076127） and the Clean Combustion ＆ Gas-solid Two-Phase Flow group in Xi＇an Jiaotong University.
文摘The effects of three factors on combustion performance of petroleum coke, Herin Coal and Shenmu Coal have been studied, including the ratio of primary air, excess air factor, and the swirling intensity of outer secondary air. The experiments were carried out on a one-dimensional furnace with dual channel swirling burner, in which temperature of center furnace, emission of air pollutants, and burn-out rate of fuel were measured. The results provide the optimal ratio of primary air, excess air factor and swirling intensity of outer secondary air for the fuels. The combustion performance of petroleum coke B is much better than petroleum coke A, but worse than Hejin coal and Shenmu coal. In addition, the burn-out rate of petroleum coke depends much more on the temperature in terminal stage of combustion than in the early stage of combustion.
文摘Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investigated experimentally. The burner consists of two coaxial jets： methane flowing out of the inner, oxidizer from the outer. The flame behavior is studied according to the proportion of oxygen in the oxidizer jet, the oxidizer and the methane jets velocities. The flame is either anchored to the burner, lifted, stationary or not or blown-out. The addition of oxygen produces a decrease of the lift height, a reduction of the length of the reaction zone and an increase in the soot emission. These results have been reported into diagrams of stability where the flame configurations are connected to the competition between the dynamic effect of the injection velocity and the chemical effect of oxygen addition.
文摘Biogas fuel is a sustainable and renewable fuel produced from anaerobic digestion of organic matter. The biogas fuel is a flammable mixture of methane and carbon dioxide with low to medium calorific values. Biogas is an alternative to conventional fossil fuels and can be used for beating, transportation and power generation. CFD （computational fluid dynamic） analysis of the combustion performance and emissions of biogas fuel in gas turbine engines is presented in this study. The main objective of this study is to understand the impact of the variability in the biogas fuel compositions and lower heating values on the combustion process. Natural gas, biogas from anaerobic digester, landfill biogas, and natural gas/biogas mixture fuels combustion were investigated in this study. The CFD results show lower peak flame temperature and CO mole fractions inside the combustor and lower NOx emissions at the combustor exit for the biogas compared to natural gas fuel. The peak flame temperature decreases by 37% for the biogas landfill （COJCH4 = 0.89） and by 22% for the biogas anaerobic digester （CO2/CH4 = 0.54） compared to natural gas fuel combustion. The peak CO mole fraction inside the combustor decreases from 9.8 × 10-2 for natural gas fuel to 2.22 × 10-4 for biogas anaerobic digester and 1.32 × 10-7 for biogas landfill. The average NOx mole fraction at the combustor exit decreases from 1.13 × 10-5 for natural gas fuel to 0.40 × 10-6 for biogas anaerobic digester and 1.06 × 10-6 for biogas landfill. The presence of non-combustible constituents in the biogas reduces the temperature of the flame and consequently the NOx emissions.
