Olis Rubin - Computer Models of Process Dynamics : From Newton to Energy Fields

1. Chapter 9

1. Chapter 2
2. Chapter 4
3. Chapter 5
4. Chapter 6
5. Chapter 7
6. Chapter 8
7. Chapter 9
8. Chapter 10
9. Appendix A
10. Appendix D

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Sarah Spurgeon, Editor in Chief

Olis Rubin

Brooklyn, Pretoria, South Africa

Copyright 2023 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey.
Published simultaneously in Canada.

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Library of Congress CataloginginPublication Data Applied for

ISBN: 9781119885658 [Hardback]

Cover Design: Wiley
Cover Images: zhengshun tang/Getty Images; Courtesy of Olis Rubin

To Judy
She brought beauty, goodness and love in my life.
We give thanks for all the blessings that we have received, together with our children

It is unworthy for excellent men to lose hours like slaves in the labor of calculation which could safely be relegated to anyone else if machines were used

Gottfried Wilhelm Leibniz (1685)

My first job was with a large electrical engineering enterprise where I had been moved to a division that designed and installed heavy duty motor drives. Our division had just acquired an analog computer that was barely large enough to simulate these machines. I was lucky to be chosen to work with my friend Gopal to see what we could achieve with this newfangled contraption. Our first project was to investigate the performance of a WardLeonard (generatormotor) set that drove a huge mining machine. The computer gave us a new window to the world, through which we could see what was happening inside the motor. All that we had learned as undergraduates now fell into place. Our basic training had considered the steady state operation of electric motors, while the lectures on dynamic behavior were entirely mathematical. We could now construct a computer model that allowed us to see the hardware, the differential equations, and the transient behavior of shafts and other variables. This is what a computer model can do for us!

Leibniz would have been elated if he could have foreseen how far machines could take us, beyond just saving us laborious calculations. Digital computers now provide us with platforms that make the physical modeling process almost effortless, leaving us free to think about more important questions. This book is written to show how a computer can be programmed to simulate motion in general. We will not include the growing market for new user interfaces, such as virtual reality or networking. These fields should be left to the expert attention of specialists.

In addition to setting the wheels in motion along a path that led to the computers of today, Leibniz was also the cofounder of differential calculus. The creation of a dynamic model is deeply rooted in mathematical analysis. We will sacrifice theoretical rigor in order to simplify the mathematics in a way that is intelligible to the working engineer and computer professional. Wherever possible we will explain mathematical operations by means of computer programs that approximate their behavior.

Thanks go to the many reviewers whose suggestions helped to bring this book into its present form. I hope that it will give readers the benefit of experience that was gained by working with many colleagues on diverse projects. Thanks to Philip de Vaal, whose enthusiastic support strengthened me to persevere in the face of setbacks, and to Becker van Niekerk, whose industry constantly invigorated me to complete this project. This is the second time that Aileen Storry has helped me bring a book to see the light of day. Thanks to the professionalism of the Wiley team, led by Kimberly, Mustaq and Patricia, that managed the publication process.

I must thank my dearest wife for her constant, unstinting support. Not only is her spelling better than mine, but she has a way of provoking me to write more lucidly for you, the reader. May it thus give you food for thought, and better equip you for the future!

Computer models are used throughout every phase of industrial research, design, and development. Simulation studies can play a large part in the concept phase of an engineering project since computer models can usually be created in less time and cost less than hardware prototypes. The very creation of such models forces everyone to delve deeper into the underlying physics of the plant. This can give valuable insight into plant operation that can aid the plant designers. If such simulators are developed before the plant is built, they can be used to evaluate the design before expensive decisions are made, and thereby help to avoid costly mistakes. In the later stages of a development program, we can greatly reduce the time and cost of commissioning and qualification by using simulator studies to reduce the scale of hardware testing. The model can also be used to determine safety limits and emergency procedures by simulating tests that would be hazardous in the real plant. There is also a growing market for training simulators to ensure the competence of the operators who will run the plant. We can foresee that this will tie up with the creation of virtual reality and the computer game industry.