The first pump text book I purchased when I began my career in pump engineering 36 years ago was Centrifugal and Axial Flow Pumps by A.J. Stepanoff. At the time, in the US anyway, that book was considered an essential text on the subject for centrifugal pump engineers. Gülich’s Centrifugal Pumps Second Edition is now today’s essential text on the subject centrifugal pump design and is truly a landmark publication. It is the most comprehensive, up-to-date reference available on the subject of centrifugal pump design.
While page count is in no way indicative of quality or usefulness, the 34 pages of foreword followed by 964 pages of main content is worthy of mention. The charts, tables, diagrams, pump and component sectionals, 3D solids renderings, and photos are high quality and of a highly consistent format throughout the book. The paper, printing and binding of the book are of an archival quality look and feel.
Nearly half of the book is devoted to pump hydraulics, performance and design. Chapter 3, “Pump hydraulics and physical concepts,” contains a masterful compendium of all essential equations needed for one-dimensional pump performance evaluation. Multi-stage pump design requires detailed evaluation of internal leakages and axial thrust – the tables of equations provided for these are outstanding. I know of no other reference providing such a complete and practical package of pump hydraulics formulae.
Practical details of pump design not readily found elsewhere are provided in the book. For example, how thick should the impeller vanes be? Most pump designers review their reference designs and scale the vane thickness up or down for the new prototype design. An experienced designer would know to increase thickness for higher head designs. As stated by Gülich, “…the thicknesses of blades, shrouds and vanes are usually chosen from experience and engineering judgment.” However, in the same Chapter 14 of the book he develops a systematic and consistent analytical approach to the problem based on flow velocity and head, static, alternating and peak stresses, material properties, fatigue, material defects, corrosion, and erosion. The pump designer, with this approach, does not necessarily have to have a reference design or experience. However, combined with experience, the analytical approach provided can be used to improve existing designs or extend them into more severe operating conditions.
Charts of normalized coefficients based on experimental results are provided for a wide array of pump performance phenomena. So the designer is not forced to select coordinate points off of a chart, an equation is usually provided. This is very useful, of course, for spreadsheet evaluations. Polynomial curve fits are used sparingly. Rather, Gülich’s equations are most often structured around relationships of the underlying variables.
120 useful summary tables are provided throughout the book. These include tables of parameters and definitions, geometry and shapes, equations and formulae, data, characteristics, diagrams, diagnostics, problems and remedies, properties, and procedures. Every important topic in the book is summarized in tabular form. By glancing at a table, the reader can quickly identify what he’s looking for and then find out additional information, as needed, covered in the chapter.
Understanding of part-load or off-peak operation of pumps is generally obtained through of years of experience with custom specification pumps, helping to resolve performance issues that routinely arise during shop testing. Chapter 5 of Gülich’s book addresses this topic from the viewpoint of observed phenomena and how basic physical principles apply. Any pump engineer called upon to resolve a difficult off-peak performance issue is likely to benefit from a review of this valuable chapter.
Good design information on axial flow pumps is relatively limited or difficult to find in published literature. Stepanoff’s Chapter 8, “Axial Flow Pumps,” has been a staple reference on the topic for more than 50 years. Centrifugal Pumps Second Editionraises the bar and packs loads of detailed design information, explanations and procedures into 24 pages, 7 tables, and 10 figures devoted to this topic.
The books’ index is above average. It’s better than most, particularly compared to some modern texts that apparently used computer software to generate the index. The problem with software-generated indexes, by the way, is that incidental appearances of subject words throughout the book are lumped together with the most relevant topic usage of those words. This adds time for the reader when looking through the book for a particular topic. Thankfully, Centrifugal Pumps Second Edition’s index does a very good job of connecting key words with relevant topics. I did find a couple of exceptions – “Complete pump characteristics,” also known as “four-quadrant” or “quadrant” curve characteristics, are called “general characteristics” in this book. “General characteristics,” at least in the US, is not a commonly used term for the topic. Also, “axial impeller” and “axial diffuser” are not listed in the index even though there’s an excellent subchapter on “Axial impellers and diffusers.” This can only be classified as an omission.
The book’s bibliography is extensive. Every important reference on the subject is included. The majority of source references are published in English and most of the others are in German. The first edition of this book, by the way, was published only in German, while the second edition is available in both German and English.
The above review is just a select sampling of what’s available in the book. Entire chapters are devoted to suction capability and cavitation, numerical flow calculations, hydraulic forces, noise and vibrations, pump operation, materials, and pump selection. A pump engineer, especially early in his or her career, will save valuable time searching elsewhere for the information that’s available in Centrifugal Pumps Second Edition.