Centrifugal pumps theory

CENTRIFUGAL-PUMP THEORY. The basic equations interrelating the power, developed head, and capacity of a centrifugal pump are derived for the ideal pump from fundamental principles of fluid dynamics. Since the performance of an actual pump differs considerably from that of an ideal one, actual pumps are designed by applying experimentally measured corrections to the ideal situation. 

Switzer, F.G., Miller, H.G. (1929). Floods. Bulletin 13. Engineering Experiment Station Ithaca. Switzer, F.G. (1930). The centrifugal pump Theory, characteristics, operation and installation. Gould Pumps, Inc. Seneca Falls NY. 

Jekat, W. K. 1992. Centrifugal pump theory. Section 2.1 in Pump Handbook, ]. Karassik et al. (Eds.), New York McGraw Hill. 

Although about half of all pumps manufactured in the world arc centrifugal (the other half are positive displacement), industry tends to use a higher quantity of centriftigal pumps. For that reason, much of this book has dealt with pump theory, applications, and problems, from a centrifugal point of view. You may think that we have abandoned PD pumps in this book. You would be wrong. 

Centrifugal pumps are made up of several components and are expected to cope in a multitude of environments, some quite hostile, fin understanding of houi they luorh, uihy they tuorh, luhy and houi they go turong and luhat to da about It can only come from a mix of theory and experience, hut the theory needs to be presented in a form which Is absorbable and Interesting if it is to he retained... 

For a particulate application involving SLS, how to choose the best equipment, to use batch or continuous operation, which filter medium to select, and what is the optimum operating conditions are concerns of engineers. Although theories are available for some SLS operations, solutions for equipment selection, process design, and optimization are still very much dependent on test and experience, and are frequently qualitative or semi-qualitative. In this section, strategy and decision networks for selection of SLS equipment, introduction of filter media, centrifugal pumps for filtration operation, and selection of filter aids by cycle analysis will be discussed. 

Drisko, J.B. (1934). Centrifugal pumps, turbines, and propellers. Basic theory and characteristics (Translation of German original by W. Spannhake). MIT Cambridge. 

Harris, E.G. (1895). Theory of the air-lift pump. Journal of the Franklin Institute 140(1) 32-52. Harris, E.G. (1903). Theory of centrifugal pumps and fans Analysis of their action, with suggestions for designers. Trans. ASCE 51 166-252. 

Hooper, E.G. (1923). Whatiscorrectdesignfor highway pavement GoociRoocii65(14) 105-106. Hooper, E.G. (1929). Discussion of New theory for the centrifugal pump. Trans. ASCE 93 44-46. 

Stepanoff, A.J. (1957). Centrifugal and axial flow pumps Theory, design, and application. Wiley New York. 

A classic reference is A. J. Stepanoff, Centrifugal and Axial Flow Pumps Theory, Design... 

Understanding the effects of solids on centrifugal pumps has been a slow process. Fairbanks (1941) developed a theory to correlate the head developed by a pump for a slurry mixture with the volumetric concentration and specific gravity of the solids. He explained that the fundamental Euler equation could be modified to account for the density and flow rate of the mixture as ... 

Crystallisation theory is covered in Volume 2, Chapter 15, and in several other texts Mullin (1992), Van Hook (1961), Nyvlt (1971) and Janie and Grootscholten (1984). Descriptions and illustrations of the many types of commercial crystalliser used can be found in these texts and in various handbooks Perry and Green (1984), Schweitzer (1988). Procedures for the scale-up and design of crystallisers are given by Mersham (1984), (1988), (1995). Bamford (1965) includes details of the ancillary equipment required vacuum pumps, circulation pumps, valves, filters, centrifuges and dryers. 

Theoretical problems with the traditional theory of the parabolic equation relate to the assumption of constant and both of which are functions of the pressure drop across the cake. The pressure drop Ap varies when centrifugal and constant rate pumps are employed. Even in constant pressure filtration, Ap varies with time. At t = 0, there is no cake, and all of the pressnre is absorbed by the medium, as shown in Fignre 22.22. As the cake builds up, the flow rate q drops and the pressure drop across the medium, p, decreases in accord with Equation (22.28) ... 

Centrifugal compressors have head-capacity curves similar to those of the more familiar centrifiigal-pump curves. Within the lower limit necessary to avoid surge and the upper limit of impeller capacity, each unit can in theory operate at any point on its curve. 

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