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Abstract: Equation of power consumption in the flow process of micro-fluid elements has been deduced in this paper by analyzing the mechanical energy equilibrium equation of microelement based on the stress relation of Newtonian fluid. By setting minimum power consumption as optimization objective and entransy consumption as constraint condition, optimization flow field equation for convective heat transfer on the basis of energy conservation equation and continuity equation are constructed. Numerical investigations of forced convective heat transfer in a circular tube based on the optimized controlling equations are conducted, and the results show that there are multi-longitude-vortexes existing in velocity field, which leads to an enhancement of heat transfer. The analysis for the heat transfer and flow resistance shows that this kind of flow field accommodates a far greater heat transfer increase than flow resistance increase, which proves that the proposed optimization theory is effective in designing high efficient heat transfer enhancement unit. [Copyright &y& Elsevier]

Abstract: Electroplating industry annually produces numerous plated workpieces for U.S. pillar industries. However, it is also a major environment polluter in forms of wastewater, sludge, and spent solution. Thus, waste source reduction for the electroplating industry is a must. In practice, when productivity and energy use efficiency are also taken into account, the design and operation of an electroplating process become very complicated and need an in-depth study. In this paper, productivity maximization, energy saving, and freshwater/wastewater minimization are simultaneously addressed for the optimal design and operation of electroplating processes, which generates a triple-objective mixed-integer dynamic optimization (MIDO) model. The MIDO model is iteratively solved by a developed methodology to obtain the 3D Pareto frontier of the optimization problem, which provides important technical supports for the design and operation of electroplating processes. The efficacy has been demonstrated with a case study on an electroplating process. [Copyright &y& Elsevier]