CFX共轭传热实例

4.5. Example Simulation of a Piezoelectric Actuated Micro-Pump （ ansys 的帮助里面的例子） Problem Description The working principle of micro-pumps is the actuation of a flexible membrane to obtain the driving pressure for the fluid flow. Electro-thermal, electrostatic, or piezoelectric actuators are most commonly used for this purpose. The benchmark problem is taken from A. Klein and demonstrated in Figure 4.6: Piezoelectric Micropump Description. This device consists of a fluid chamber with a deformable membrane at the top. The membrane is actuated by a piezoelectric layer during pump operation. To estimate the fluid damping and inertial forces on the membrane, a simplified process of the membrane actuation is considered here. With the diaphragm in the neutral position and the chamber filled with the working fluid, the PZT layer is actuated at t = 0 with an electric field, which is maintained at a constant level subsequently. Figure 4.6: Piezoelectric Micropump Description ANSYS coupled field element SOLID5 with displacement and voltage DOFs is used for the piezoelectric material and SOLID95 is used for the silicon membrane. Air at 25 degrees Celsius is used as the working fluid for the CFX solver. The following material properties were used for the silicon: You ng's Modu lu s: 1.689e11 Pa Poisson's ratio: 0.3 Density : 2329 kg/m3 The following material properties were used for the piezoelectric material (PZT4): Density : 7500 kg/m3 X and Z Permittiv ity : 804.6 (Polar ax is along Y ax is) Y Permittiv ity : 659.7 The elasticity stiffness matrix is shown here (N/m2 units): The piezoelectric stress matrix is shown here (C/m2 units): Figure 4.7: Model Dimensions This model has a 0.1 mm thickness...