共查询到20条相似文献，搜索用时 15 毫秒
1.
The heat conduction characteristic of glass curtain wall was investigated. Based on one dimensional steady heat conduction theory, the numerical calculation model of glass system thermal transmittance was set up by using insulating glass as an example. Based on two dimensional steady heat conduction theory and finite element method, both the thermal transfer matrix and temperature load array of 3 DOFs triangular element were derived. Then the revised formulas about the heat transfer matrix and temperature load array under the boundary conditions of constant heat flux, heat convective, radiation and coupled of them were also derived. Then the numerical calculation models of glass curtain wall frame and linear thermal transmittance were set up. The program TJCW based on the Visual C++ and ObjectARX was developed for calculating the thermal transmittance of glass curtain wall and was validated by contrast with the results calculated by thermal software LBNL. Finally, TJCW program was used to calculate and check the thermal transmittance of glass curtain wall in a practical project. The results indicate that the thermal transmittance of glass curtain wall can be calculated correctly by adopting the presented model, and the program based on this model can be used in energy conservation calculation and analysis in the actual projects. 相似文献
2.
日光温室揭帘时间农业天气预报指数的确定 总被引：3，自引：3，他引：0
为了提升气象服务能力,合理掌握日光温室保温帘揭盖时间,进而提升生产水平和经济效益,利用日光温室揭开保温帘时间的数学模型,对安塞冬季日光温室保温帘揭开时间进行分析验证。根据安塞县温度和光照气候资料,计算出安塞冬季各旬平均揭帘时间,并利用数学模型和天气预报,建立了揭帘农用天气预报指数,用于指导农业生产。结果表明,数学模型适合在安塞应用,天气预报指数符合生产实际,指导意义明确,按计算所得保温帘揭开时间达到了预期效果。 相似文献
3.
As the domestic technology of selective catalytic reduction(SCR) has not been mature.A assembled-parameter dynamic mathematical model is established for the primary chemistry reaction process in SCR reactor.The mass balance equation of the NH3 adsorption-desorption on the catalyzer surface and six gas components,and total energy balance equation in SCR reactor are set up respectively.A dynamic simulation model has developed by using MATLAB simulation tool.The steady calculation for model is carried on.Based on the established dynamic simulation model,two dynamic simulation experiments have been done,which include the simulation experiment of step disturbance about NOx concentration and temperature.The simulation results current is correctl.The analyzed results indicate that the established dynamic mathematical model for SCR reactor is credible,and prove that the simulation model is practical. 相似文献
4.
The structure and energy conservation characteristics of hybrid desiccant cooling system with condensation heat recovery are introduced briefly. Based on the first and second law of thermodynamics, a system thermodynamic model is established and the solution process given in a diagram. The dehumidification capacity is calculated under different exergy efficiency and indoor sensible heat conditions. The calculation results show that the desiccant wheel barely can compensate for the humidity load of outdoor air under with a ventilation rate of providing fresh air once per hour; when the fresh air rate of ventilation is limited to 0.5 times per hour, however, the desiccant wheel possess sufficient capacity under relatively large wheel exergy efficiency and high sensible heat load. 相似文献
5.
Ni Lin Zhang Xiangwei 《保鲜与加工》1997,(5):33-38
Some conversion calculation formulas from the XYZ axises to PRB axises of CNC Pipe Bender are set up.The calculation model of graph simulation about moving process of Pipe Bender is set up.Finaly a CAD software is programmed. 相似文献
6.
地埋管地源热泵换热器的换热性能受到不同地质结构的影响。以武汉和重庆地区的典型地质构成为边界条件,建立了三维地埋管的单孔双U管换热模型,通过模型计算,获得了两种地质条件下的地埋管换热性能,以重庆地区的地源热泵热响应测试结果以及工程运行数据出发,对模型的计算结果进行了验证,结果表明,模型吻合度较好,可以应用于工程分析。以模型为条件,进行地质结构对换热性能的影响度分析,预测了两地地埋管地源热泵的换热性能并计算得到换热器的平均换热系数分别为武汉地区K1=1.65（W/m·K）,重庆地区K2=1.51（W/m·K）。 相似文献
7.
To provide gist of air distribution design for subway island-platform and appraise the blue print of air distribution design,a three-dimension model of typical island-platform was constructed.Then it got an appropriate temperature difference for the supply air to optimize the air conditioning system design for subway island-platform.The physical model was set up with standard turbulence.Based on factual heat and wet load,a boundary condition for the simulation was analyzed.The air flow of subway island-platform was simulated with Computational Fluid Dynamics(CFD).The Simulated temperature fields were the same as the tested temperature fields.Then the Computational Fluid Dynamics simulation can simulate and forecast subway island-platform temperature fields accurately with standard model.Thus it can provide gist for air-conditional system design of subway island-platform. 相似文献
8.
Simulation method for multi-machine and multi-task crane scheduling in steelmaking plant 总被引：1，自引：0，他引：1
It is of great significance in steel complex to link production flow between work stations and control production rhythm by cranes. Crane scheduling is a multi-machine multi-task problem which limits temporal and spatial constraints and production plan. A simulation model based on evolution rules to solve temporal and spatial constraints is proposed. Its objective is to guarantee execution of production plan in steelmaking plant. And match between cranes and production task on working span is conducted to fulfill temporal constraints between multi-tasks and spatial constraints among multi-cranes. Simulation rules including task allocation, conflicts eliminating and task finishing are also proposed to dominate simulation process. This model avoids difficulties of theoretical calculation for crane scheduling problem. Offline test in a steelmaking plant shows that it is available to make a crane scheduling without conflicts between cranes and plans, which provides a guideline for production scheduling. 相似文献
9.
A sewage-water shell-tube heat exchanger with the function of de-fouling was proposed and designed for sewage-source heat pump. Its new simulation program which relies on a distribution parameter computational method was set up. Then the model was solved with the method of Matrix Control. Based on the model, the distribution of bilateral fluid temperature were studied, under the conditions of different flow rates and heat exchange area before and after the de-fouling. Results showed that there will be heat anti-transfer phenomenon if the heat exchanger area is bigger than need and the region of this phenomenon was point out. Setting the function of auto-de-fouling in shell-tube heat exchanger and reducing the equipment's volume accordingly can make the sewage-water heat exchanger run in the best conditions. 相似文献
10.
To overcome the precision machining difficulty of non-circular gear, a convex pitch curve of non-circular gear and worm grinding method is presented. Firstly, worm wheel is reduced to rack cutter and a rack machining convex pitch curves of non-circular gears sport model is set up. Then based on the structure of CNC worm wheel grinding machine tools and machining principle, electronic gear box of machine tools is designed and active and following axes are planned. At the mean time, the synchronous coefficient of machine tools between synchronization is deduced by machining principle of equal arc-length, and interaction models of grinding are established. At last, the worm wheel manual presetting cutter methods with non-circular gear are given and worm grinding wheel mounting angle, axial position and axial location parameter can be adjusted along the gear. 相似文献
11.
In order to study the vibration characteristics and radiation noise of wind power speed-increase gearbox, a torsional vibration model of wind power speed-increase gearbox is established based on the analysis of supporting stiffness of bearing and contact stiffness of gear pairs. By solving the vibration differential equation with the help of Matlab, the frequency and corresponding vibration mode are obtained. With taking stiffness excitation, error exaction and meshing impact exaction into account, the dynamic finite element model of speed-increase gearbox is set up, and the dynamic response simulation is carried out. Regarding vibration displacement of the nodes on gearbox surface as boundary condition, an acoustic boundary element model of speed-increase gearbox is built. The surface acoustic pressure of gearbox and the radiation noise of field points are solved by the direct boundary element method. The results show that there is a great difference between torsion frequency and excitation frequency of wind power speed-increase gearbox, and so the resonance doesn't occur. The maximum structural noise and radiation noise mainly appear near the double octave of the gears meshing frequency of high-speed grade. 相似文献
12.
The improved geometrical constraint model of open-pit mine boundary optimum and its application 总被引：1，自引：0，他引：1
This paper develops the improved geometric constraint model (IGCM) based on the 3D block model. The variable-slope excavation cones of each block have been abstracted to collections of nodes and directed edges, and the optimization method has been introduced using the set theory. The IGCM consists of the optimized collection nodes and directed edges. The algorithm based on IGCM has been actualized in DIMINE digital mine system, and is applied to an actual open pit mine boundary optimization engineering. The results shows that IGCM can accurately simulate variable slope angles in any azimuth and elevation changes, and adapt to all open pit mine boundary optimum problems in any complex geological conditions, calculation speed and accurate. It provides a new and effective method for the variable-slope open pit mine boundary optimization problem in complex geological conditions. 相似文献
13.
Influence of Backfill Air Gap on Soil Temperature Recovery in Ground coupled Heat Pumps 总被引：2，自引：0，他引：2
Air gap may easily emerge in the progress of backfill in ground heat exchange due to field operation problems. The single U tube three dimensional numerical heat transfer model is set up and there are 3 kinds of backfill air gap assumptions for computational analysis, which are the most common situations in practical projects. Different air gap situations will have considerable effects on soil heat transfer, especially the factor of soil temperature recovery performance, which is investigated in this research, and there is practical project operating data for the comparison confirmation with the theoretical calculation results in inlet and outlet water temperatures. It can be concluded that the backfill air gap will increase the soil average excess temperature in the period of recovery inside the place where the air gap is, and degrade the heat transfer performance of the ground heat exchange. 相似文献
14.
A theoretical model is developed for the dropwise condensation heat transfer on the horizontal circular surface with radial gradient surface energy based on the heat transfer model of individual condensate drop and the size distribution model of condensate drop on homogeneous condensation surface.The effect of variation of contact angle on the gradient surface on condensation heat transfer and condensate drop size distribution is taken account of in this model.The theoretical calculation method was obtained to predict the dropwise condensation heat transfer coefficient on the horizontal circular surface with radial gradient surface energy under various wall subcooled temperature,contact angle profile on wall surface,and working fluid.The effects of surface energy gradient,wall subcooled temperature,and thermophysical properties of condensate on the condensation heat transfer are discussed respectively.The calculation results show that the condensation heat transfer coefficient increases slightly with the increase of wall subcooled temperature.As latent heat and surface tension increasing,the condensation heat transfer coefficient increases.A larger surface energy gradient induces a larger condensation heat transfer coefficient. 相似文献
15.
无架豇豆种子高产栽培技术方案研究 总被引：1，自引：0，他引：1
采用二次回归正交旋转设计方法，经过计算机计算，建立了播期、密度和矮壮素施用量等3项栽培技术与美国无架豇豆产量的数学模型并通过模拟寻优，筛选出每公顷产量2140～2650kg的综合技术优化组合方案。 相似文献
16.
The purpose of a power system is to deliver the power the customers require in real time, on demand, within acceptable voltage and frequency limit, and in a reliable and economic manner. Using NLPNN (New Linear Programming Neural Network) model, the behavior analysis of power system under fault conditions is carried through. The stability and convergence theorems are set up to obtain the resolution for the problem of the load curtailment strategy. A new way is open up to evaluate the reliability of power systems and the great progress in calculation analysis model is achieved. The new calculation technique and theory foundation of reliability evaluation are supplied. 相似文献
17.
For the benefit of environment protection and sustainable economic development especially in western china, to build more hydroelectric power stations is a basic policy of our government. Xiluodu project is the biggest underground hydroelectric power station. which includes 18 power generation units with a capacity more than 12 600 MW. By establish a set of heat and humidity balance equations applying on the Xiluodu project underground workshop with its boundary conditions, this paper has present an one_dimensional heat conduction model to simulate its dynamical heat transfer process. On the purpose of compare deferent design schemes of HVAC system, a package of software for numerical simulation is developed. In this paper,we have also recommend some criteria for the evaluation of HVAC system design schemes. The computation result has show that if utilizing the reservoir water and AC chiller to process the air,combing other anti_humidification technical measures,it will assure the anticipated air quality of underground facilities. 相似文献
18.
This paper introduces the importance of developing the Ground-Source Heat pump and describes the prospects of it.with the method used abroad to acquire the temperature profiles within surrounding soil of the underground heat exchanger with buried tubes, in this paper the line heat source theory and thermal resistance network analysis method were used to set up the heat transfer model.The original temperature of the ground is determined by calculation and is compared with test results. Experiments of running single tube and running three series connection tubes are carried out on the built underground exchangers of vertical buried tube type.And the data which can provide reference for the Ground-Soure Heat pump technique are acquired. 相似文献
19.
This paper analyzes the heat transfer principle of temperature sensor fire detector, establishes mathematical model of heat transfer with considering the effect of radiation heat transfer and presents a new calculation method for the response time. The results of calculation show that when the environment temperature is rather low and the response temperature is set higher, the effect of radiation heat transfer on response time shouldn't be neglected. This paper may be helpful in appraising fire safety and designing alarm system. 相似文献
20.
Zeng Zhong 《保鲜与加工》1992,(3):6-10
There are three actions of different features exerted upon the work surface by the abrasive grains on the working surface of the wheel during grinding process: they are elastic scratching, plastic pressing and cutting. The heat transformed by these three actions as well as the rubbing between the wheel bond and the work surface contributes to the integrated average temperature on the contact zone between the wheel and the work. In this paper the measurement and calculation of this integrated average temperature and the temperature distribution in the work are given, the influences of various grinding parameters are also studied. 相似文献