Abstract: There exists serious problems in the no-moving-part valves (NMPV) used by the piezoelectric pump presently: being complex in structure or bringing on huge vortex whose pressure and velocity vary dramatically in the tubes, which will go against the aim of transporting living cells and the long-chain-macromolecule cells in the areas of medical treatment, sanitation and health care. Aiming at these problems, a new type of the piezoelectric pump―valveless piezoelectric pump with Y-shape tubes is developed, and simulative and experimental researches are applied on the pump. Combined with the needs of transporting blood and fluid in the area of medical treatment, the advantages and disadvantages of several typical no-moving-part valves are analyzed, and the properties of the piezoelectric pump with Y-shape tubes and its tubes are introduced. Theoretical analysis is applied on the pump and the theoretical formula of the pump flow rate is established. Based on the finite element method (FEM), the numerical simulation of the fluid flow situation inside the Y-shape tubes is carried out, the law of pressure change of the Y-shape tubes along the positive and reverse directions are obtained, and the conclusion that the vortex occurs in the Y-shape tube is much more feeble than that in the taper tubes, is obtained, the flow resistances of the Y-shape tubes are also calculated. A comparison is made between the theoretical and experimental flow rate for the piezoelectric valveless pump with Y-shape tubes, the results indicate that the minimum and maximum relative errors between the two results turn out to be 7% and 13% respectively. Therefore, the validity and correctness of the theoretical analysis and the numerical simulation are proved.

Key words: Finite element method, Flow resistance, Piezoelectric pump, Y-shape conduit