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A numerical model was developed to simulate the momentum, heat, and mass transfer in the fuel cell channels at steady state and developing laminar flow with constant fluid properties. The continuity, momentum, energy, and species equations were solved for humidified air and humidified H2 with constant mass flux suction boundary condition for O2 in the cathode and H2 in the anode channels. A finite-volume method was used to solve the equations in two-dimensional cases. Friction coefficient was related to the flowrate, whereas Nusselt and Sherwood numbers were, respectively, related to the heat and mass transfer in the flow channels. The distribution of local [ABSTRACT FROM AUTHOR]

Micro-genetic algorithm (μGA) was employed to inverse boundary design of a radiant enclosure with absorbing—emitting medium. The goal of inverse analysis was to find a set of heaters over some parts of the boundary, called the heater surface, to satisfy the desired heat flux profile over the design surface. The direct problem of radiative heat transfer was solved by the discrete transfer method. The inverse problem was solved through the minimization of an appropriate objective function using the μGA. A novel smoothing criterion was used to achieve a smooth distribution of heaters over the heater surface. The desired heat fluxes over the design surface were well recovered by employing a smooth distribution of heaters over the heater surface. The ability of this method to solve the inverse problem in irregular geometries was demonstrated by an example. [ABSTRACT FROM AUTHOR]

An optimization technique is applied to design of heat transfer systems in which both conduction and radiation are important. The inverse methodology is used to find a set of heater inputs over the heater surface to produce the desired temperature and heat flux distributions over the design surface. A combination of the finite-element method with the discrete transfer method is used to solve the conductive-radiative heat transfer equation. The conjugate gradient method is used for minimization of an objective function, which is expressed by the sum of square residuals between estimated and desired heat fluxes over the design surface. The performance and accuracy of the present method for solving inverse conduction-radiation heat transfer problems is evaluated by comparing the results with a benchmark problem and a numerical experiment for an irregular two-dimensional case. [ABSTRACT FROM AUTHOR]

An inverse analysis is employed to estimate the unknown heat flux distribution over the heater surface of an irregular 2-D domain with participating media from the knowledge of a desired temperature and heat flux distributions over a given design surface. The discrete transfer method is employed to solve the radiative transfer equation and a conjugate gradient method is used for minimization of an objective function, which is expressed by the sum of square residuals between estimated and desired heat fluxes. The performance of the present technique for inverse radiation analysis is evaluated by several numerical experiments. [ABSTRACT FROM AUTHOR]

In this investigation, a model has been developed to predict the performance of a Texaco controlled combustion stratified charge engine (TCCS). This model uses the k–ℇ turbulence model to determine characteristic velocities for heat transfer calculations, which has only one empirical constant, in contrast to Woschni's equation in which separate constants are used for each process in the four-stroke cycle to determine the velocity for use in Reynolds number calculation. The modified Keck and Blizard model is used for combustion calculation by considering the rapid compression effects on turbulence intensity. Comparison of the model predictions with available experimental data shows a good agreement. Moreover, the program has a high flexibility for parametric studies to calculate performance parameters such as thermal efficiency, pressure, specific fuel consumption, temperature, fluid flow into and out of the cylinder, friction losses, heat transfer, flow field in the cylinder and so on. [ABSTRACT FROM AUTHOR]