A heat pump assisted fluidized bed grain drying experimental system wasdeveloped. Based on this system, a serial of experiments was performed under four kinds of air cycleconditions. According to the experimental anal...A heat pump assisted fluidized bed grain drying experimental system wasdeveloped. Based on this system, a serial of experiments was performed under four kinds of air cycleconditions. According to the experimental analysis, an appropriate drying medium-air cycle for theheat pump assisted fluidized bed drying equipment was decided, which is different from the commonlyused heat pump assisted drying system. The experimental results concerning the drying operationperformance of the new system show that the averaged coefficient of performance (COP) can reach morethan 2.5. The economical evaluation was performed and the power consumption for removing a kilogramwater from grains was about 0.485 kW-h/kg (H_2O), which shows its reasonable commercial efficiencyand great application potentiality in future market.展开更多
A 2-dimension axisymmetric model was developed by the finite-differencemethod, which can be used to predict the transient temperature field and thermal profile of workrolls in the hot strip rolling process. To demonst...A 2-dimension axisymmetric model was developed by the finite-differencemethod, which can be used to predict the transient temperature field and thermal profile of workrolls in the hot strip rolling process. To demonstrate the accuracy and reliability of the solutiondeveloped, the calculation results were compared with the production data of a 1700 mm hot striprolling mill and good agreement was found between them. The effect of strip width and roll shiftingon the thermal expansion of the work rolls was studied. It is found that the strip width has markedeffect on the efficient thermal crown. Initially, when the rolling strip changes from narrow towide, a bigger efficient thermal crown can be quickly achieved; afterwards, when the rolling stripchanges from wide to narrow, not only the influence of uneven wear can be reduced but also theexcessive efficient thermal crown can be avoided. It is also found that the work roll shifting has adeterminate but not obvious effect on the reduction of the efficient thermal crown, and will makethe strip shape unstable without being used properly.展开更多
A parametric model of cutting temperature generated in end milling process is developed according to the thermal mechanism of end milling as an intermittent operation, which periodically repeats the cycle of heating u...A parametric model of cutting temperature generated in end milling process is developed according to the thermal mechanism of end milling as an intermittent operation, which periodically repeats the cycle of heating under cutting and cooling under non-cutting. It shows that cutting speed and the tool-workpiece engagement condition are determinative for tool temperature in the operation. The suggested model was investigated by tests of AlTiN coated endmill machining hardened die steel JIS SKD61, where cutting temperature on the flank face of tool was measured with an optical fiber type radiation thermometer. Experimental results show that the tendency of cutting temperature to increase with cutting speed and engagement angle is intensified with the progressing tool wear.展开更多
The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative c...The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative characteristics of the medium is proposed. It is proved that decreasing the particle size of coatings can increase the transmission depth of radiative heat and get higher emissivity and absorptivity both theoretically and practically. Ultra-attenuation and nanocrystallization will bring a brilliant prospect to the development of radiative coatings.展开更多
The mathematical model for the thermal process of billets rolling has beenestablished, including transporting in air and temperature-holding cover, descaling withhigh-pressure water, and the process of rolling and coo...The mathematical model for the thermal process of billets rolling has beenestablished, including transporting in air and temperature-holding cover, descaling withhigh-pressure water, and the process of rolling and cooling in water box. The calculated data by themodel have been compared with the measured data and the results show that the model is right andcreditable. Based on the model, the main thermal characters of rolling line have been simulated andthe influence of all the parameters on the temperature of rolling has been analyzed.展开更多
A very simple model based on the Quadrupole method was used in thetheoretical analysis of thermal diffusivity of composite materials of Cu-PVC, PVC-Cu-PVC, andCu-PVC-Cu. The use of MATLAB software with a return to rea...A very simple model based on the Quadrupole method was used in thetheoretical analysis of thermal diffusivity of composite materials of Cu-PVC, PVC-Cu-PVC, andCu-PVC-Cu. The use of MATLAB software with a return to real space using the Stehfest algorithm makesthe time of calculation very short. The thermal responses on the rear face of each consideredsample, which determine the thermal diffusivity were represented. A mathematical demonstration whichconfirmed the results was given. Thermal diffusivity determined from the rear face thermalresponses were compared with the results of the thermal diffusivity calculated by considering thecomposite materials to be homogeneous, and a discussion on the two kinds of results was provided.展开更多
Flow structure and heat transfer characteristics of an axisymmetric circularjet impinging on a hot 1Cr18Ni9Ti medium plate have been simulated numerically using computationalfluid dynamic (CFD) code. The relation betw...Flow structure and heat transfer characteristics of an axisymmetric circularjet impinging on a hot 1Cr18Ni9Ti medium plate have been simulated numerically using computationalfluid dynamic (CFD) code. The relation between flow field of jet impingement and its heat transfercapability is analyzed, and the phenomenon that heat transfer at stagnation point is smaller thanthat of points directly around is discussed. The simulation result provides boundary conditions forthermal analysis of medium plate quenching.展开更多
A suitable similarity transformation is introduced to reduce the laminarboundary layer equations of power law fluids to a class of singular nonlinear two-point boundaryvalue problems. The kin friction and shear stress...A suitable similarity transformation is introduced to reduce the laminarboundary layer equations of power law fluids to a class of singular nonlinear two-point boundaryvalue problems. The kin friction and shear stress distributions for boundary layer flow over amoving flat plate are investigated by utilizing the shooting technique. Results indicate that foreach fixed value of the power law exponent n or the velocity ratio parameter xi, the skin frictionand shear stress decrease with the increasing of n or xi respectively.展开更多
The transport behavior of free boundary value problems for a class ofgeneralized diffusion equations was studied. Suitable similarity transformations were used toconvert the problems into a class of singular nonlinear...The transport behavior of free boundary value problems for a class ofgeneralized diffusion equations was studied. Suitable similarity transformations were used toconvert the problems into a class of singular nonlinear two-point boundary value problems andsimilarity solutions were numerical presented for different representations of heat conductionfunction, convection function, heat flux function, and power law parameters by utilizing theshooting technique. The results revealed the flux transfer mechanism and the character as well asthe effects of parameters on the solutions.展开更多
For predicting and controlling the melted depth of bottomelectrode during the process of steelmaking, the water-cooling steel-stick electrode is taken as an example, to analyze the process ofheat transfer, then 3D mat...For predicting and controlling the melted depth of bottomelectrode during the process of steelmaking, the water-cooling steel-stick electrode is taken as an example, to analyze the process ofheat transfer, then 3D mathematical model by control capacity methodis built. At the same time, the measurement on the melted depth ofbottom electrode is conducted which verified the correctness of thebuilt mathematical model. On the base of verification, all kinds ofkey parameters are calculated through the application and a series ofresults are simulated. Finally, the optimum parameters are found andthe service life of bottom electrode is prolonged.展开更多
The problem of momentum and heat transfer in a compressible boundary layerbehind a thin expansion wave was solved by the application of the similarity transformation and theshooting technique. Utilizing the analytical...The problem of momentum and heat transfer in a compressible boundary layerbehind a thin expansion wave was solved by the application of the similarity transformation and theshooting technique. Utilizing the analytical expression of a two-point boundary value problem formomentum transfer, the energy boundary layer solution was represented as a function of thedimensionless velocity, and as the parameters of the Prandtl number, the velocity ratio, and thetemperature ratio.展开更多
From the microstructure of heat radiation, the interaction between theincident heat radiative wave and the electromagnetism syntonic wave is analyzed to reveal theemission, absorption, transmission and reflection mech...From the microstructure of heat radiation, the interaction between theincident heat radiative wave and the electromagnetism syntonic wave is analyzed to reveal theemission, absorption, transmission and reflection mechanisms of the incident heat radiative wave inmaterials. Based on Lorentz dispersion theory, the effect of optical parameters on heat radiativecharacteristics is also analyzed. The method of ultra-attenuation and nanocrystallization improvingthe heat radiative characteristics of the material and the emissivity dispersion of theultra-attenuated materials are brought to light.展开更多
Based on the detailed analysis of the third coke oven in BaoSteel, a feedbackcontrol strategy of longitudinal temperature and finished carbonization time of coke ovens wasproposed and it was applied to the third coke ...Based on the detailed analysis of the third coke oven in BaoSteel, a feedbackcontrol strategy of longitudinal temperature and finished carbonization time of coke ovens wasproposed and it was applied to the third coke oven in BaoSteel. As a result, the ratio of theinstance that the absolute deviation of the longitudinal temperature is within +- 7 deg C and thefinished carbonization time within +- 10 min is more than 80 percent, having acquired the patentsaving effect of an energy consumption lowered by 2.92 percent. At the same time, it can provide anexample for the same coke ovens inside and outside the nation.展开更多
A linear mass-spring system model of a tractor-semitrailer together withdriver body parts and sprung seat is presented. Natural frequencies of the system are calculated andresponse of components in the system to road ...A linear mass-spring system model of a tractor-semitrailer together withdriver body parts and sprung seat is presented. Natural frequencies of the system are calculated andresponse of components in the system to road roughness is completed by means of computer simulationand power spectral density (PSD) approach in all of road conditions and loading cases. The resultsshow that the severest situation of response of the system occurs when the road in rough conditionand vehicle unladen. The most sensitive frequency to human body parts is around 0.9 Hz, and modeltypes of a human body seem to be not significant to the response of a heavy tractor-semitrailersystem, including to the response of the driver himself.展开更多
A novel method for generating a rolling schedule is presented, which is fundamentally different from the existing ones. KDD (knowledge discovery in database) techniques are applied for discovering association rules be...A novel method for generating a rolling schedule is presented, which is fundamentally different from the existing ones. KDD (knowledge discovery in database) techniques are applied for discovering association rules between rolling parameters in a large database of rolling operation, and based on these rules, the schedule for the crucial last six finishing passes is generated. Operational evaluation shows that the schedule generated by the new method outperforms that generated by existing methods. It also shows how in this application the human's domain knowledge is applied to speed up the KDD process and to ensure the validity of the knowledge discovered.展开更多
Employing Simulated Annealing Algorithm (SAA) and many measured data, acalculation model of work roll wear was built in the 2 800 mm 4-high mill of Wuhan Iron and Steel(Group) Co. (WISCO). The model was a semi-theory ...Employing Simulated Annealing Algorithm (SAA) and many measured data, acalculation model of work roll wear was built in the 2 800 mm 4-high mill of Wuhan Iron and Steel(Group) Co. (WISCO). The model was a semi-theory practical formula. Its pattern and magnitude werestill hardly defined with classical optimization methods. But the problem could be resolved by SAA.It was pretty high precision to predict the values for the wear profiles of work roll in a rollingunit. After one-year application, the results show that the model is feasible in engineering, and itcan be applied to predict the wear profiles of work roll in other mills.展开更多
A second order heat equation with convection in an infinite medium isstudied. Suitable similarity transformations are used to reduce the parabolic heat equation to aClass of singular nonlinear boundary value problems....A second order heat equation with convection in an infinite medium isstudied. Suitable similarity transformations are used to reduce the parabolic heat equation to aClass of singular nonlinear boundary value problems. Numerical solutions are presented for differentrepresehtations of heat conduction, heat convection, heat flux, and power law parameters byutilizing the shooting technique. The results reveal the heat transfer characteristic and the effectof parameters on the solutions.展开更多
Temperature distribution and control have been investigated in a liquefiedpetroleum gas (LPG) fluidized bed with hollow corundum spheres (A1_2O_3) of 0.867-1.212 mm indiameter at moderately high temperatures (800-1100...Temperature distribution and control have been investigated in a liquefiedpetroleum gas (LPG) fluidized bed with hollow corundum spheres (A1_2O_3) of 0.867-1.212 mm indiameter at moderately high temperatures (800-1100℃). Experiments were carried out for the airconsumption coefficient α in the range of 0.3 to 1.0 and the fluidization number N in the range of1.3 to 3.0. Particle properties, initial bed height, α and N all affect temperature distribution inthe bed. Bed temperature can be adjusted about 200℃ by combined the adjusting of α and N.展开更多
基金This work was financially supported by the Education Department of China (No.00020)
文摘A heat pump assisted fluidized bed grain drying experimental system wasdeveloped. Based on this system, a serial of experiments was performed under four kinds of air cycleconditions. According to the experimental analysis, an appropriate drying medium-air cycle for theheat pump assisted fluidized bed drying equipment was decided, which is different from the commonlyused heat pump assisted drying system. The experimental results concerning the drying operationperformance of the new system show that the averaged coefficient of performance (COP) can reach morethan 2.5. The economical evaluation was performed and the power consumption for removing a kilogramwater from grains was about 0.485 kW-h/kg (H_2O), which shows its reasonable commercial efficiencyand great application potentiality in future market.
基金This work was financially supported by the Excellent Young Teachers Program of the Education Ministry of China (No. 261)
文摘A 2-dimension axisymmetric model was developed by the finite-differencemethod, which can be used to predict the transient temperature field and thermal profile of workrolls in the hot strip rolling process. To demonstrate the accuracy and reliability of the solutiondeveloped, the calculation results were compared with the production data of a 1700 mm hot striprolling mill and good agreement was found between them. The effect of strip width and roll shiftingon the thermal expansion of the work rolls was studied. It is found that the strip width has markedeffect on the efficient thermal crown. Initially, when the rolling strip changes from narrow towide, a bigger efficient thermal crown can be quickly achieved; afterwards, when the rolling stripchanges from wide to narrow, not only the influence of uneven wear can be reduced but also theexcessive efficient thermal crown can be avoided. It is also found that the work roll shifting has adeterminate but not obvious effect on the reduction of the efficient thermal crown, and will makethe strip shape unstable without being used properly.
文摘A parametric model of cutting temperature generated in end milling process is developed according to the thermal mechanism of end milling as an intermittent operation, which periodically repeats the cycle of heating under cutting and cooling under non-cutting. It shows that cutting speed and the tool-workpiece engagement condition are determinative for tool temperature in the operation. The suggested model was investigated by tests of AlTiN coated endmill machining hardened die steel JIS SKD61, where cutting temperature on the flank face of tool was measured with an optical fiber type radiation thermometer. Experimental results show that the tendency of cutting temperature to increase with cutting speed and engagement angle is intensified with the progressing tool wear.
文摘The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative characteristics of the medium is proposed. It is proved that decreasing the particle size of coatings can increase the transmission depth of radiative heat and get higher emissivity and absorptivity both theoretically and practically. Ultra-attenuation and nanocrystallization will bring a brilliant prospect to the development of radiative coatings.
文摘The mathematical model for the thermal process of billets rolling has beenestablished, including transporting in air and temperature-holding cover, descaling withhigh-pressure water, and the process of rolling and cooling in water box. The calculated data by themodel have been compared with the measured data and the results show that the model is right andcreditable. Based on the model, the main thermal characters of rolling line have been simulated andthe influence of all the parameters on the temperature of rolling has been analyzed.
基金The research work is financially supported by National Natural Science Foundation of China (No.50276003).
文摘A very simple model based on the Quadrupole method was used in thetheoretical analysis of thermal diffusivity of composite materials of Cu-PVC, PVC-Cu-PVC, andCu-PVC-Cu. The use of MATLAB software with a return to real space using the Stehfest algorithm makesthe time of calculation very short. The thermal responses on the rear face of each consideredsample, which determine the thermal diffusivity were represented. A mathematical demonstration whichconfirmed the results was given. Thermal diffusivity determined from the rear face thermalresponses were compared with the results of the thermal diffusivity calculated by considering thecomposite materials to be homogeneous, and a discussion on the two kinds of results was provided.
文摘Flow structure and heat transfer characteristics of an axisymmetric circularjet impinging on a hot 1Cr18Ni9Ti medium plate have been simulated numerically using computationalfluid dynamic (CFD) code. The relation between flow field of jet impingement and its heat transfercapability is analyzed, and the phenomenon that heat transfer at stagnation point is smaller thanthat of points directly around is discussed. The simulation result provides boundary conditions forthermal analysis of medium plate quenching.
基金This work was financially supported by the Cross-Century Talents Projects of Educational Ministry, China and the "973" Key Item(
文摘A suitable similarity transformation is introduced to reduce the laminarboundary layer equations of power law fluids to a class of singular nonlinear two-point boundaryvalue problems. The kin friction and shear stress distributions for boundary layer flow over amoving flat plate are investigated by utilizing the shooting technique. Results indicate that foreach fixed value of the power law exponent n or the velocity ratio parameter xi, the skin frictionand shear stress decrease with the increasing of n or xi respectively.
基金This work was financially supported by the Cross-Century Talents Projects of Educational Ministry of China and the 973 Key Item (No. G1998061510).]
文摘The transport behavior of free boundary value problems for a class ofgeneralized diffusion equations was studied. Suitable similarity transformations were used toconvert the problems into a class of singular nonlinear two-point boundary value problems andsimilarity solutions were numerical presented for different representations of heat conductionfunction, convection function, heat flux function, and power law parameters by utilizing theshooting technique. The results revealed the flux transfer mechanism and the character as well asthe effects of parameters on the solutions.
文摘For predicting and controlling the melted depth of bottomelectrode during the process of steelmaking, the water-cooling steel-stick electrode is taken as an example, to analyze the process ofheat transfer, then 3D mathematical model by control capacity methodis built. At the same time, the measurement on the melted depth ofbottom electrode is conducted which verified the correctness of thebuilt mathematical model. On the base of verification, all kinds ofkey parameters are calculated through the application and a series ofresults are simulated. Finally, the optimum parameters are found andthe service life of bottom electrode is prolonged.
基金This work was supported by the "Cross-Century Talents Projects of the Educational Ministry of China"the "Projects of Investigations of Post Graduate School, University of Science and Technology Beijing".
文摘The problem of momentum and heat transfer in a compressible boundary layerbehind a thin expansion wave was solved by the application of the similarity transformation and theshooting technique. Utilizing the analytical expression of a two-point boundary value problem formomentum transfer, the energy boundary layer solution was represented as a function of thedimensionless velocity, and as the parameters of the Prandtl number, the velocity ratio, and thetemperature ratio.
文摘From the microstructure of heat radiation, the interaction between theincident heat radiative wave and the electromagnetism syntonic wave is analyzed to reveal theemission, absorption, transmission and reflection mechanisms of the incident heat radiative wave inmaterials. Based on Lorentz dispersion theory, the effect of optical parameters on heat radiativecharacteristics is also analyzed. The method of ultra-attenuation and nanocrystallization improvingthe heat radiative characteristics of the material and the emissivity dispersion of theultra-attenuated materials are brought to light.
文摘Based on the detailed analysis of the third coke oven in BaoSteel, a feedbackcontrol strategy of longitudinal temperature and finished carbonization time of coke ovens wasproposed and it was applied to the third coke oven in BaoSteel. As a result, the ratio of theinstance that the absolute deviation of the longitudinal temperature is within +- 7 deg C and thefinished carbonization time within +- 10 min is more than 80 percent, having acquired the patentsaving effect of an energy consumption lowered by 2.92 percent. At the same time, it can provide anexample for the same coke ovens inside and outside the nation.
文摘A linear mass-spring system model of a tractor-semitrailer together withdriver body parts and sprung seat is presented. Natural frequencies of the system are calculated andresponse of components in the system to road roughness is completed by means of computer simulationand power spectral density (PSD) approach in all of road conditions and loading cases. The resultsshow that the severest situation of response of the system occurs when the road in rough conditionand vehicle unladen. The most sensitive frequency to human body parts is around 0.9 Hz, and modeltypes of a human body seem to be not significant to the response of a heavy tractor-semitrailersystem, including to the response of the driver himself.
文摘A novel method for generating a rolling schedule is presented, which is fundamentally different from the existing ones. KDD (knowledge discovery in database) techniques are applied for discovering association rules between rolling parameters in a large database of rolling operation, and based on these rules, the schedule for the crucial last six finishing passes is generated. Operational evaluation shows that the schedule generated by the new method outperforms that generated by existing methods. It also shows how in this application the human's domain knowledge is applied to speed up the KDD process and to ensure the validity of the knowledge discovered.
基金[This work was financially supported by the National Natural Science Foundation of China (No.59835170).]
文摘Employing Simulated Annealing Algorithm (SAA) and many measured data, acalculation model of work roll wear was built in the 2 800 mm 4-high mill of Wuhan Iron and Steel(Group) Co. (WISCO). The model was a semi-theory practical formula. Its pattern and magnitude werestill hardly defined with classical optimization methods. But the problem could be resolved by SAA.It was pretty high precision to predict the values for the wear profiles of work roll in a rollingunit. After one-year application, the results show that the model is feasible in engineering, and itcan be applied to predict the wear profiles of work roll in other mills.
基金This work was supported by Cross-Century Talents Projects of Educational Ministry of China the "973" Key Foundation under the contract No.G1998061510.]
文摘A second order heat equation with convection in an infinite medium isstudied. Suitable similarity transformations are used to reduce the parabolic heat equation to aClass of singular nonlinear boundary value problems. Numerical solutions are presented for differentrepresehtations of heat conduction, heat convection, heat flux, and power law parameters byutilizing the shooting technique. The results reveal the heat transfer characteristic and the effectof parameters on the solutions.
基金This work was financially suppoded by the Key Project Foundation for Science and Technology Research by the Education Ministry of China (No.00020).
文摘Temperature distribution and control have been investigated in a liquefiedpetroleum gas (LPG) fluidized bed with hollow corundum spheres (A1_2O_3) of 0.867-1.212 mm indiameter at moderately high temperatures (800-1100℃). Experiments were carried out for the airconsumption coefficient α in the range of 0.3 to 1.0 and the fluidization number N in the range of1.3 to 3.0. Particle properties, initial bed height, α and N all affect temperature distribution inthe bed. Bed temperature can be adjusted about 200℃ by combined the adjusting of α and N.
