Similarity criteria of units for pumping low-viscosity food liquids by peripheral pumps

Abstract

Various types of pumps are used at food industry enterprises for pumping processing media. Perifirium pumps (PP) can work with a wide range of products that do not contain solid impurities and can create a large pressure at a relatively low flow rate. It is recommended to use PP with large values of the end gap between the impeller and the housing, having a linear pressure characteristic. Reducing the gap can lead to clogging of the unit and complicating its flushing between operations. Manufacturers of PP in the open access place the characteristics of pumps in dimensional form and, as a rule, only the dependence of the pressure on the flow rate. Calculations performed on the basis of the test results of JSC HMS "Livgidromash" have made it possible to determine the similarity criteria for the pumping units under consideration and to investigate their impact on performance characteristics. It has been established that for all the considered PP, the linear load characteristics (flow-head dependence) are similar; for the flow-power characteristics, one similarity criterion (θ) has been defined, when determining the efficiency (efficiency), two criteria (θ, K) have been defined. The similarity criteria for determining the flow and pressure at the working point are two dimensionless quantities (a, hC), with an increase in which the dimensionless flow decreases and the pressure increases. When determining the dimensionless power at the working point, three similarity criteria have been established (a, hC, θ), when determining the efficiency- four (a, hC, θ, K). An increase in the criteria a, hC, θ leads to an increase in the dimensionless power expended at the working point and a decrease in efficiency. The increase in efficiency occurs only with an increase in the K value.