Graphic-analytical method of defining pressure characteristics of centrifugal-vortex pumps

The problem of forming effective pumping equipment for difficult operating conditions in different environments is rather vexed. For the last years new technologies in pump-building sphere that are directed to solving the problem in this work has been introduced. Nowadays for the liquid transportation in the water-supply system, in the food and oil industries centrifugal-vortex pumps have got wide application. Their design feature is characterized by two staged: centrifugal and vortex. Centrifugal-vortex pumps have rather good operating showings in the results of successful using of the positive qualities if the centrifugal working wheel and vortex one. They are fixed on the common shaft. Unfortunately there are few scientific works, devoted to the experimental and theoretical problems, that decelerate improvement of this kind of pumps. The improvement of the centrifugal-vortex pumps brakes the absence of analytic dependences. They describe the characteristics of these pumps. The main item of this article is the receiving of the analytic expressions for the description of a pressure characteristic H=f(Q) of a centrifugal-vortex pump. A great number of experiments were done to solve this assigned task. Due to it we've got the results for building pressure characteristics in the frequency rotation 1000, 2000, 3000 rpm. The article presented experiment's data with the centrifugal-vortex pump defining the force of pressure, depending on supply. Graphic-analytical method of defining pressure characteristics of centrifugalvortex pumps is presented. Method of graphic-analytical construction of pressure characteristics is propounded. Calculations with the given formula of pressure characteristics for different number of turns, as well as the comparison of calculation curve lines with experimental results are made. The normalization of pressure and supply is done. Formula for constructing of dimensionless characteristics in different frequency rotation is suggested.