A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace （TTRHF） in compact strip production （CSP）. To accurately predict the heat exchange...A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace （TTRHF） in compact strip production （CSP）. To accurately predict the heat exchange in the furnace, modeling of the complex gas energy-balance equation in volume zones was considered, and the heat transfer model of heating slabs and wall lines was coupled with the radiative heat transfer model to identify the surface zonal temperature. With numerical simulation, the temperature fields of gas, slabs, and wall lines in the furnace under one typical working condition were carefully accounted and analyzed. The fundamental theory for analyzing the thermal process in TI＇RI-IF was provided.展开更多
A complete process of grid generation for complex practical aircraft is described with a twin tail fighter as an example. Euler equations are discretized in the generated multiblock grid by a finite volume method and...A complete process of grid generation for complex practical aircraft is described with a twin tail fighter as an example. Euler equations are discretized in the generated multiblock grid by a finite volume method and solved by a three stage explicit time stepping scheme in each block with some extra treatments of interface at each step. The predicted aerodynamic coefficients and vortical flow field are reasonable.展开更多
When solving the complex radiative heat transfer problems in reheating furnaces, there are a number of difficulties with the traditional zonal methods. To circumvent these difficulties, a new simplified method was pro...When solving the complex radiative heat transfer problems in reheating furnaces, there are a number of difficulties with the traditional zonal methods. To circumvent these difficulties, a new simplified method was pro- posed, which employed imaginary planes, referred to as the imaginary plane model. With the new model, crown wall reduction process was simplified. Therefore, every model zone could be treated as a closed square cavity. It could also solve the problem of radiative blocking in industrial furnaces more effectively. Besides, the new imaginary plane based model may lead to a problem that the denominator was zero. This problem was solved by transforming the ex- pressions of reflex heat flux in the model. The model was capable of dealing with the systems that included black sur- faces. The model was validated by considering the heat transfer in a reheating furnace where the temperature fields in the furnace chamber （including the steel, wall and gas） were obtained. A detailed comparison was made between the simulation and the black box experiment. The results show that the new model developed was valid and accurate.展开更多
This paper proposes a numerical method for the study of ventilation efficiency in buildings. The developed model is validated with the experimental results of Nielsen who tested the isothermal flow in a scaled model o...This paper proposes a numerical method for the study of ventilation efficiency in buildings. The developed model is validated with the experimental results of Nielsen who tested the isothermal flow in a scaled model of a ventilated room. A zonal method is used to predict airflow patterns in the same ventilated room. The different equations governing the flow in the room were coded in Matlab for different operating conditions, different zonal configurations of the room and different number of cells （control volumes）. The efficiency of the ventilation was determined by calculating the number of ACH （air changes per hour） for each cell. The present results show the importance of the inlet air flow rate, the space resolution and the jet inlet dimensions on the determination of air quality.展开更多
This study explained the importance of environmental protection in tourism development and illustrated the relationship between recreational resource valuation and environmental consideration.We compare different mode...This study explained the importance of environmental protection in tourism development and illustrated the relationship between recreational resource valuation and environmental consideration.We compare different models of travel cost method and reiterates long-time existing problems of multi-destination and treats of time opportunity cost(TOC).Taking Jiayuguan's cultural sights as an example,we establish an updated method called multidestination zonal tourism cost method to evaluate the recreational values(RVs) of selected three cultural sights.We divide trip packages of Jiayuguan's tourists into 11 portfolios.Each portfolio can be seen as a separate commodity,and each commodity has its own demand curve.According to demand curves we can calculate consumer surplus(CS) of different portfolios of tourist destinations and later we sum up the total travel costs(including travel expenditure and TOC) and CS to come to the RVs of each portfolio.We then apply suitable proportions to calculate the RVs between different destinations in the portfolio.In the end,we add up all the RVs calculated for the objective destination.Using this method,we draw conclusions that Jiayuguan's RV in 2006 includes national and international values,summing up to 738.4762 million yuan.The tourist expenditure,CS and TOC of Jiayuguan is proportionating 62.96,32.28 and 4.76%,respectively.This study is also an example of non-market valuation of cultural tourism resources.展开更多
The transient coupled radiative and conductive heat transfer in a semitransparent composite under the complexboundary conditidns is investigated by the ray tracing method in combination with Hottel’s zonal method and...The transient coupled radiative and conductive heat transfer in a semitransparent composite under the complexboundary conditidns is investigated by the ray tracing method in combination with Hottel’s zonal method and thecontrol-volume method. The composite is composed of tWo plane layers of nonscattering sendtransparent media withthe different thermophysical Properties in each layer. Both boundals surfaces and the internal interface aresemitransparent. The reflections are assUmed diffuse or specular. The transient temperature distributions in thecomposite are Obtained for the combined thermal boundary conditions of incident radiation and convective heat transfer.Under diffuse reflection, the resultS in this paper are separately compared with the steady and transient results ofPrevious work. The comparison shows the reliability and the high calculating accuracy of the formulas derived in thespaper. The Present analysis includes the effeCts of the optical thickness, the conduchon-radiation parameter, the spectralproperty and the renechve mode on the transient temperature distributions.展开更多
文摘A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace （TTRHF） in compact strip production （CSP）. To accurately predict the heat exchange in the furnace, modeling of the complex gas energy-balance equation in volume zones was considered, and the heat transfer model of heating slabs and wall lines was coupled with the radiative heat transfer model to identify the surface zonal temperature. With numerical simulation, the temperature fields of gas, slabs, and wall lines in the furnace under one typical working condition were carefully accounted and analyzed. The fundamental theory for analyzing the thermal process in TI＇RI-IF was provided.
文摘A complete process of grid generation for complex practical aircraft is described with a twin tail fighter as an example. Euler equations are discretized in the generated multiblock grid by a finite volume method and solved by a three stage explicit time stepping scheme in each block with some extra treatments of interface at each step. The predicted aerodynamic coefficients and vortical flow field are reasonable.
基金Item Sponsored by National High Technology Research and Development Program(863Program)of China(2011AA060104)
文摘When solving the complex radiative heat transfer problems in reheating furnaces, there are a number of difficulties with the traditional zonal methods. To circumvent these difficulties, a new simplified method was pro- posed, which employed imaginary planes, referred to as the imaginary plane model. With the new model, crown wall reduction process was simplified. Therefore, every model zone could be treated as a closed square cavity. It could also solve the problem of radiative blocking in industrial furnaces more effectively. Besides, the new imaginary plane based model may lead to a problem that the denominator was zero. This problem was solved by transforming the ex- pressions of reflex heat flux in the model. The model was capable of dealing with the systems that included black sur- faces. The model was validated by considering the heat transfer in a reheating furnace where the temperature fields in the furnace chamber （including the steel, wall and gas） were obtained. A detailed comparison was made between the simulation and the black box experiment. The results show that the new model developed was valid and accurate.
文摘This paper proposes a numerical method for the study of ventilation efficiency in buildings. The developed model is validated with the experimental results of Nielsen who tested the isothermal flow in a scaled model of a ventilated room. A zonal method is used to predict airflow patterns in the same ventilated room. The different equations governing the flow in the room were coded in Matlab for different operating conditions, different zonal configurations of the room and different number of cells （control volumes）. The efficiency of the ventilation was determined by calculating the number of ACH （air changes per hour） for each cell. The present results show the importance of the inlet air flow rate, the space resolution and the jet inlet dimensions on the determination of air quality.
基金support of Key Project of Chinese Ministry of Education (Grantno.170170)
文摘This study explained the importance of environmental protection in tourism development and illustrated the relationship between recreational resource valuation and environmental consideration.We compare different models of travel cost method and reiterates long-time existing problems of multi-destination and treats of time opportunity cost(TOC).Taking Jiayuguan's cultural sights as an example,we establish an updated method called multidestination zonal tourism cost method to evaluate the recreational values(RVs) of selected three cultural sights.We divide trip packages of Jiayuguan's tourists into 11 portfolios.Each portfolio can be seen as a separate commodity,and each commodity has its own demand curve.According to demand curves we can calculate consumer surplus(CS) of different portfolios of tourist destinations and later we sum up the total travel costs(including travel expenditure and TOC) and CS to come to the RVs of each portfolio.We then apply suitable proportions to calculate the RVs between different destinations in the portfolio.In the end,we add up all the RVs calculated for the objective destination.Using this method,we draw conclusions that Jiayuguan's RV in 2006 includes national and international values,summing up to 738.4762 million yuan.The tourist expenditure,CS and TOC of Jiayuguan is proportionating 62.96,32.28 and 4.76%,respectively.This study is also an example of non-market valuation of cultural tourism resources.
文摘The transient coupled radiative and conductive heat transfer in a semitransparent composite under the complexboundary conditidns is investigated by the ray tracing method in combination with Hottel’s zonal method and thecontrol-volume method. The composite is composed of tWo plane layers of nonscattering sendtransparent media withthe different thermophysical Properties in each layer. Both boundals surfaces and the internal interface aresemitransparent. The reflections are assUmed diffuse or specular. The transient temperature distributions in thecomposite are Obtained for the combined thermal boundary conditions of incident radiation and convective heat transfer.Under diffuse reflection, the resultS in this paper are separately compared with the steady and transient results ofPrevious work. The comparison shows the reliability and the high calculating accuracy of the formulas derived in thespaper. The Present analysis includes the effeCts of the optical thickness, the conduchon-radiation parameter, the spectralproperty and the renechve mode on the transient temperature distributions.
