CALCULATING MODEL AND CHARACTERISTICS SINGLE ACTION VALVELESS PISTON PUMP
The working process of a single acting piston pump, the valves of which are replaced by fluidic diodes-flow elements containing no moving mechanical parts and characterized by significant dependence of the flow rate at the same head difference upon direction of the flow is examined. A calculating model of the process is represented. It is based on splitting a complex flow up to couple of simple ones: caused by harmonic movement of the piston and head difference between the dampers. Length of the suction and pressure line was estimated negligible and their diameters are equal. Analysis of the calculating model revealed dimensional and non-dimensional parameters of the pump, the most important of which are the head and flow, displacement and frequency of piston movement, diodicity and direct resistance of the fluidic diodes, the relative acreage of the piston. Analytical expressions of the flow-pressure characteristics and the efficiency of the pump are obtained. It's displayed that unlike check-valve pump's characteristic fluidic diodes controlled pump's one is downward sloping curve. Having head decreasing the flow of the pump is being increased reaching peak value at point of head equal to zero. There is an interval of the characteristic's curve where pump's efficiency is optimal. The analysis of the pump's parameters influence on its characteristics is displayed. It's revealed that having either frequency of the movement of the piston or displacement and diodicity of fluidic diodes increasing realizable head and flow of the pump are also increasing. Efficiency of the valveless pump basically depends on diodicity of the fluidic diodes calculated according to resistances. When diodicity's value is 40 efficiency's value is 26 % and when diodicity's value is 60 efficiency's value is 33 %.