This paper presents the optimization of 3D valveless diaphragm micropump for medical applications.The pump comprises an inlet and outlet diffuser connected to the main chamber equipped with a periodically moving diaph...This paper presents the optimization of 3D valveless diaphragm micropump for medical applications.The pump comprises an inlet and outlet diffuser connected to the main chamber equipped with a periodically moving diaphragm that generates the unsteady flow within the device.The optimization,which is related exclusively to the diaphragm motion,aims at maximizing the net flowrate and minimizing the backflow at the outlet diffuser.All CFD analyses are performed using an in-house cut-cell method,based on the finite volume approach,on a many-processor system.To reduce the optimization turn-around time,two optimization methods,a gradient-free evolutionary algorithm enhanced by surrogate evaluation models and a gradient-based(GB)method are synergistically used.To support the GB optimization,the continuous adjoint method that computes the gradient of the objectives with respect to the design variables has been developed and programmed.Using the hybrid optimization method,the Pareto front of non-dominated solutions,in the two-objective space,is computed.Finally,a couple of optimal solutions selected from the computed Pareto front are re-evaluated by considering uncertainties in the operating conditions;these are quantified using the polynomial chaos expansion method.展开更多
In the present paper, flow configurations of cavitating flow around a straight NACA0009 foil with a gap between the foil tip and sidewall are investigated numerically by large eddy simulation（LES） coupled with Zwart...In the present paper, flow configurations of cavitating flow around a straight NACA0009 foil with a gap between the foil tip and sidewall are investigated numerically by large eddy simulation（LES） coupled with Zwart-Gerber-Belamri（ZGB） cavitation model. A Cartesian cut-cell method is used for mesh generation, which is of good orthogonality and high quality. A good agreement is obtained between simulation and experiment. Two influencing factors on vorticity distributions, the interaction between different vortices and the occurrence of cavitation, are discussed in detail based on the numerical results. A series of ？-shaped loops are observed during the development of the induced vortex, which is a result of the instability of vortex pair. This finding may provide a new viewpoint to control the evolution of tip-leakage vortex（TLV） cavitation. Moreover, it is found that the dilatation term plays a much more important role in the evolution of TLV cavitation compared with that in sheet cavitation.展开更多
文摘This paper presents the optimization of 3D valveless diaphragm micropump for medical applications.The pump comprises an inlet and outlet diffuser connected to the main chamber equipped with a periodically moving diaphragm that generates the unsteady flow within the device.The optimization,which is related exclusively to the diaphragm motion,aims at maximizing the net flowrate and minimizing the backflow at the outlet diffuser.All CFD analyses are performed using an in-house cut-cell method,based on the finite volume approach,on a many-processor system.To reduce the optimization turn-around time,two optimization methods,a gradient-free evolutionary algorithm enhanced by surrogate evaluation models and a gradient-based(GB)method are synergistically used.To support the GB optimization,the continuous adjoint method that computes the gradient of the objectives with respect to the design variables has been developed and programmed.Using the hybrid optimization method,the Pareto front of non-dominated solutions,in the two-objective space,is computed.Finally,a couple of optimal solutions selected from the computed Pareto front are re-evaluated by considering uncertainties in the operating conditions;these are quantified using the polynomial chaos expansion method.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51576143,11772239 and 91752105)the Science and Technology on Water Jet Propulsion Laboratory(Grant No.61422230101162223002)
文摘In the present paper, flow configurations of cavitating flow around a straight NACA0009 foil with a gap between the foil tip and sidewall are investigated numerically by large eddy simulation（LES） coupled with Zwart-Gerber-Belamri（ZGB） cavitation model. A Cartesian cut-cell method is used for mesh generation, which is of good orthogonality and high quality. A good agreement is obtained between simulation and experiment. Two influencing factors on vorticity distributions, the interaction between different vortices and the occurrence of cavitation, are discussed in detail based on the numerical results. A series of ？-shaped loops are observed during the development of the induced vortex, which is a result of the instability of vortex pair. This finding may provide a new viewpoint to control the evolution of tip-leakage vortex（TLV） cavitation. Moreover, it is found that the dilatation term plays a much more important role in the evolution of TLV cavitation compared with that in sheet cavitation.
基金National Natural Science Foundation of China(31801632)Science and Technology Innovation Foundation of Shanxi(2019L0396)Shanxi Agricultural of University Research Grant(2016YJ04)。
