Experiment for Condensing Heat Transfer Performance in a New Type of Horizontal Three Dimensional Inner Microfin Tubes

A new type of three dimenstional inner microfin tube is devoloped. Under four different pressures and in the range of condensing mass velocities from 33 to 153 kg/m2 . s,and by the experimental study of the three kinds of tubes with different microfin parameters, the performances of the condensation heat transfer for R11 in the horizontal microfin tubes and obtained. The experiments show that the inner microfin tube is a hopeful and nighty effective condensing heat transfer enhancement tube.     

Calculation of Maintenance Cost Based on the Proportional Life Setback Model

Maintenance cost is one of the most difficult parts to calculate in variant-cost, for it s decided by the reliability of components. As an important factor of reliability, life is largely affected by maintenance. The proportional life prolonged model based on maintenance is presented firsdy. Based on this model, the function of Mainenance--Life--Cost is deduced. Which provides a new method for power plant to calculate maintenance cost more accurately.     

Dropwise Condensation Heat Transfer Coefficient on the Horizontal Circular Surface with Radial Gradient Surface Energy

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.     

Transmission Congestion Management Based on Power Influence Coefficient

Basing eliminating on the idea that the generator who has the most influence on the power flow of line is mostly in favor of transmission congestion, the model of congestion management with the object of minimizing adjustments of bufions varied with generation outputs is proposed. It can eliminate the congestion effectively by judging the generators who should be adjusted and the amounts of adjustment. The test on IEEE-RTS24 buses system and other practical systems show that the proposed method is effective.     

Analysis of Heat Transfer and Optimal Parameters of Multi-louvered Fin Condenser

The authors conduct the experimental study and optimal computing for the condenser of automobile air conditioner. The especially the properties of heat transfer and flow at the side of air when using shutter fin. The authors the influence of several combinations of fin's geometry parameter to heat transfer and flow resistance. The maximal heat transfer is used as a criterion relation to select the fin's geometry parameters in the same facing air area of condenser. Furthermore, a program is designed to conduct optimal computing, and the computing results are basically consistent with experimental results. It shows that the optimal method is reasonable and the results can be applied to engineering practice.     

Performance Simulation of EHE for 300MW CFB

With the development of circulating fluidized bed boiler(CFB),the study field of external heat exchanger(EHE) is greater in extent and degree.In order to research the working process of EHE,the model which deals with flow and heat transfer of EHE for 300MW CFB of Dong Fang Boiler Grou PCo.Ltd.is presented.Based on the cell modeling theory,the EHE is divided into several chamber by heating surfaces.The mass and energy conservation equations of each cell have been developed according to some reasonable assumption.The complete mathematical model has been compiled by Fortran and solved by classical Algorithm of Runge-Kutta.The static test and perturbation experiment of simulating model has been performed.The simulation results show that the model has been reached the steady state rapidly,the dynamic responses are reasonable and the modeling presented in the paper is reliable and appropriate.     

Computation of Three-Dimensional Temperature Distribution and Thermal Analysis to Integrated Circuit Substrates

The exact three di me nsional temperatu re distribution and thermal analysiS to inte-grated circuit substrates have been presen ted by means of numerical method of a fin ite difference.Thismethed.which will overcome the di fficuItv of mathematical deduction mav be consltieredas an analytical way aided by com puters for thermal design of electron ic compon ents.     

Power Frequency Electric Field Caused by EHV Lines and Its Effect

Mathematical model of power frequency electric field is established based on Charge Simulation Method(CSM) to analyze power frequency electric field caused by EHV lines with overhead ground wires and its effect, which are entering the megalopolis. Calculative method on the electric field under the transmission lines is analyzed and validated. According to the criterion of environmental evaluation, the distributing characteristic of electric field is summarized, in case of various arrangement manners of lines. At last, some advice and methods of eliminating electric field under the transmission lines entering the megalopolis is proposed with regard to protecting environment.     

Simulation Investigation for the Regulating Characteristics of Real and Reactive Power of Asynchronized Turbogenerators

This paper discuas the controlling principle of asynchronized turbogenerators,deduces their mathematical model,and studies their regulating characteristics of real and reactive power(or voltage)by means of simulation calculation of operating characteristics for a 200MW asychronlzed turbogenerator.The conclusion is that the asychronlzed tubogenerators not only can regulate real and reactive power independently but also has an excellent dynamic performance.     

A Vovel Constracture of Combinatorial Knowledge Base for the Expert System of Eletrical Switching

By comparing the techniges of the production and the logic predicate for knowledge representation, this paper presents a kind of constructure of combinatorial knowledge base applied to the expert system for switch operation in electric power system . This constructure of knowledge base to be expanded and revised easily,and it is cinvenitnt to build the general shell of the expert system.