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2011 | Buch

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History of Rotating Machinery Dynamics

verfasst von: J. S. Rao

Verlag: Springer Netherlands

Buchreihe : History of Mechanism and Machine Science

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

This book starts with the invention of the wheel nearly 5000 years ago, and via Archimedes, Aristotle and Hero describes the first practical applications such as water wheels and grinding wheels, pushing on to more rigorous scientific research by inquiring minds such as Leonardo da Vinci and Copernicus in later ages. Newton and Leibniz followed, and beam structures received maximum attention three centuries ago. As focus shifts and related disciplines such as mathematics and physics also develop, slowly turbomachines and rotor and blade dynamics as we know the subject now take shape. While the book traces the events leading to Laval and Parsons Turbines, the emphasis is on rotor and blade dynamics aspects that pushed these turbines to their limits in the last century. The tabular and graphical methods developed in the pre-computer era have taken different form in the last fifty years through finite element methods. The methods evolved in the last century are discussed in detail to help modern day designers and researchers. This book will be useful to young researchers and engineers in industry and educational institutions engaged in rotor and blade dynamics work in understanding the past and the present developments and what is expected in future. Faculty and industry engineers can benefit from this broad perspective history in formulating their developmental plans.

Inhaltsverzeichnis

Frontmatter

Beginnings of the Wheel

Abstract

The dates of the Stone Age vary considerably for different parts of the world. It began about 2 million years ago and ended in different parts from 6000 to 2500 BC. Throughout the immense time span of the Stone Age, see Scarre [2] and Schick and Nicholas [3], vast changes occurred in climate and in other conditions affecting human culture. Humans themselves evolved into their modern form during the latter part of it. The Stone Age has been divided accordingly into three periods: the Paleolithic, Mesolithic and Neolithic, see Technology of Man [5].

J. S. Rao

Science before the Medieval Period

Abstract

Greeks took the elementary mathematics of the Egyptians and developed it into tools to serve the physicist and the engineer of the day. About 600 BC geometry from Egypt was imported and Greeks began to develop it and arithmetic into separate branches of mathematical science. In the next several hundred years, Hippocrates (460- BC), Aristotle (384–322 BC), Euclid (323–285 BC), and others systematized what was then known about geometry and arithmetic [2].

J. S. Rao

Water Wheels

Abstract

In all likelihood, the earliest tools employed by humankind for crushing or grinding seeds, nuts, and other food-stuffs consisted of little more than a flat rock, upon which the material was crushed by pounding with a stone or tree branch. The archaeological records show that as early as 30,000 years ago, Cro-Magnon artists employed the mortar and pestle to grind and mix the pigments they used to create their magnificent “cave-art”.

J. S. Rao

Wind Mills

Abstract

Over 5,000 years ago, the ancient Egyptians used wind to sail ships on the Nile River. While the proliferation of water mills was in full swing, windmills appeared to harness more inanimate energy by employing wind sails. The wind wheel of Heron of Alexandria marks one of the first known instances in history of wind powering a machine [1]. The first practical windmills were the vertical axle windmills invented in eastern Persia, as recorded by the Persian geographer Estakhri in the 9th century, see Hassan and Hill [2]. Prototypes of windmills were probably known in Persia (present day Iran) as early as the 7th century AD with their sails mounted on a vertical axis, (see Figure 14.2). Towards the end of the 12th century, windmills with sails mounted on a horizontal axis appeared in Europe; the first of this kind probably appeared in Normandy, England. These are post mills, where the sails and machinery are mounted on a stout post and the entire apparatus has to be rotated to face the wind.

J. S. Rao

Renaissance and Scientific Revolution

Abstract

Technology has been traditionally the realm of craftsmen working by rough rules of trial and error. The existing knowledge base was a mass of confusion in the absence of a unified understanding of the behavioral motion of solids and fluids [7, 31, 35]. The man of knowledge was a natural philosopher rather than a scientist.

The reawakening of scientific thought was brought about during the Renaissance Period (1400-1600) and carried into the period of the scientific revolution. Leonardo da Vinci (1452-1519) has recently been credited for some fundamental contributions to solid mechanics, fluid mechanics and mechanical design much before the scientific revolution. His contributions appear in Codex Madrid I, one of two remarkable notebooks that were discovered in 1967 in the National Library of Spain (Madrid), after being misplaced for nearly 500 years, see [1, 45]. He correctly concluded that, in bending of beams due to transverse loads, plane cross-sections remain plane before and after bending and rotate as shown in Figure 5.1. Da Vinci lacked Hooke’s law and calculus to complete the theory; we had to wait for Galileo to improve this further before Euler and Bernoulli formed correct equations for simple bending.

J. S. Rao

Renaissance Engineers

Abstract

Medieval and Renaissance Europe possessed only one effective heat engine, the combustion engine in the form of the cannon (Figure 6.1) [1].

The credit for making pressure exerted by the atmosphere entirely explicit belongs to Otto von Guericke (reprint 1963), who in 1672 published the famous book in which he described his air pump and the experiments that he made with it from the mid 1650s onwards. His famous demonstration is illustrated in Figure 6.2. Once it was understood that atmosphere exerts pressure, it was a matter of creating a vacuum and allowing the atmospheric pressure to move the piston in a cylinder.

J. S. Rao

Industrial Revolution

Abstract

Between 1780 and 1850, in a space of just seven decades, the face of England was changed by a far-reaching revolution, without precedent in the history of mankind.

Glasgow University had one of the Newcomen engines for its natural philosophy class. In 1763, one hundred years after the birth of Newcomen, this apparatus went out of order and Professor John Anderson gave JamesWatt (1736-1819) the opportunity to repair it. After the repair and while experimenting with it, Watt was struck by the enormous consumption of steam because, at every stroke, the cylinder and piston had to be heated to the temperature of boiling water and cooled again. This prevented the apparatus from making, with the available boiler capacity, more than a few strokes every minute. He quickly realized that wastage of steam was inherent in the design of the engine and became obsessed with the idea of finding some remedy. From the discovery of Joseph Black (1728-1799), he deduced that the loss of latent heat was the most serious defect in the Newcomen engine [2]. The work of James Watt [3] is thus the key application of science to engineering which led to the birth of the industrial revolution.

J. S. Rao

Turbomachines

Abstract

During the 2nd century BC, Hero demonstrated the principle of a reaction turbine, but could not realize any useful work. Despite the scientific revolution followed by the industrial revolution, James Watt, while attempting to build a steam turbine, came to the conclusion that it could not be built given the state of contemporary technology.

J. S. Rao

Fundamentals of Elasticity

Abstract

Fundamentals of Theory of Elasticity or physics of deformable bodies were established during the scientific revolution. Engineers would call these deformable bodies as structures. Hooke’s law was discovered in 1660. Robert Hooke (1635–1703) was an English physicist. His important law of elasticity, known as Hooke’s law (1660), states that the stretching of a solid is proportional to the force applied to it. He published his law in 1678 [4].

J. S. Rao

Energy Methods

Abstract

The fundamental principle in Physics is that the energy in the Universe is conserved; it can change in form but cannot be created or destroyed. Energy can be in various forms, important of these forms for vibration and rotor dynamics study is kinetic energy and potential energy (strain energy). In freely vibrating systems, these energies keep continuously change in these forms thus producing oscillatory motion for the mass.

J. S. Rao

20th Century Graphical and Numerical Methods

Abstract

With the rapid growth of rotating machinery from the beginning of the 20th century, there was a need to determine the natural frequencies in an industrial environment by rapid means that can be established to handle various design problems. Methods were devised to streamline and develop fool-proof methods which semi-skilled engineers could handle in the shortest possible time with minimum errors. These methods continued to play a significant role until recently; they are only now being phased out in industry in favor of finite element methods.

J. S. Rao

Matrix Methods

Abstract

The kinetic and potential energies in a free vibration problem are expressible as homogeneous quadratic forms in the velocities q̇_i and coordinates q _i respectively, leads to important conclusions to be drawn concerning normal coordinates.

J. S. Rao

Finite Element Methods

Abstract

Once the possibility of computers was foreseen, the engineering community turned its attention to solving complex elasticity and structural analysis problems rather than depending on an approximate strength of materials approach. It also allowed the engineering community to depend less on factors of a safety approach and to remove or reduce to a considerable extent the unknown factors and thus render more accurate designs. Finite element methods allowing more accurate predictions reduced costly experimentation and introduced simulation, thus achieving cheaper but more accurate designs before testing prototypes.

J. S. Rao

Rotor Dynamics Methods

Abstract

The industrial revolution began with reciprocating steam engines as devised by James Watt in 1780, and the 19th century witnessed a rapid expansion in various industrial sectors. Unfortunately, the reciprocating steam engine had several problems because of external combustion and excessive alternating load due to reciprocating masses that limited speeds and capacities. The industry was looking for non-reciprocating systems, purely rotating systems that could usher in an era of socalled “Vibration Free” engines. The dynamics of rotating structures are different from those of stationary structures. Basically, all the vibration phenomena will be valid, however, there are several differences and we have to set up new procedures for handling rotors and their vibratory phenomena.

J. S. Rao

Transfer Matrix Methods

Abstract

Linke [6] measured the main current and exciting current after a short circuit. The main current rose to about 32 times the normal current. Brown Boverie Co. [1] reported that for a 3000 RPM 8800 kva machine, the maximum short circuit current is about 10-20 times that at full load. The current diminishes rapidly, but the steady state value is reached only after several seconds.

J. S. Rao

Finite Element Methods for Rotor Dynamics

Abstract

The finite element method for rotors was first developed by Ruhl and Booker [29]. Nelson and McVaugh [16] extended this to include gyroscopic effects. The effects of axial torque were included by Zorzi and Nelson [37] and Nelson [15] gave rotor dynamics elements with the Timoshenko beam theory. For details on the finite element method, see also [1, 4, 10, 11, 19].

J. S. Rao

Bladed Disks

Abstract

Bladed-disk vibrations were well studied because of the critical fatigue problems. They are the most stressed systems in machines. Campbell [5], Stodola [52] and Sezawa [48] are amongst the first few who studied the bladed-disks. Kroon [25] applied difference calculus to the case of lashed blades to determine the blade stresses. Though no vibrations were considered, this paper is the first attempt to point out that the whole blade group should be considered. Smith [51] made a two-dimensional free vibrational analysis in the tangential direction using a dynamic stiffness matrix method on a six and twenty bladed group. His contribution was most significant since the group frequencies and mode shapes were determined for the first time as shown in Figure 17.1.

J. S. Rao

Lifing

Abstract

Turbine bladed disks continue to fail because of fatigue caused by resonant stresses; one of the major failures in the 1990s was reported in a nuclear machine in Narora, India. Bearing failures caused machine trip and rubbing caused blade fatigue (see Figure 18.1).

Albert Wilhelm (1838) is recognized as the first person to record observations of metal fatigue. While working in the Mining and Forestry Office in Clausthal, Germany, in 1829, he observed, studied and reported the failure of iron mine-hoist chains arising from repeated small loadings, the first recorded account of metal fatigue, see [31].

J. S. Rao

Optimization

Abstract

Optimization had its roots in the scientific revolution period and thus is one of the oldest sciences [8]. For industrial applications, however it remained dormant until recent times. The pioneering work of modern structural topology can be traced back to 1981 when Cheng and Olhoff, see Keng-Tuno [5], introduced the concept of microstructure to structural optimization in studying the optimum thickness design of a solid elastic plate for minimum compliance. A continuum approach to structural topology optimization was first introduced by Bendsøe and Kikuchi [1]. Optimization of finite element-based structures is acknowledged as a useful methodology for achieving important improvements in product design and is widely used in automotive and aerospace industries.

J. S. Rao

Concluding Remarks

Abstract

In just over three centuries, through a scientific revolution, mankind became scientists with an understanding of continuum phenomena, solids, fluids, thermodynamics and other manifestations of nature that existed around them.

Enabled by these sciences, a second revolution consisted of making stone tools to elevate man over the rest of the animal kingdom and to replace human labor with animal labor. The third revolution replaced animal labor by machines.

J. S. Rao

Backmatter

Titel: History of Rotating Machinery Dynamics
verfasst von: J. S. Rao
Verlag: Springer Netherlands
Electronic ISBN: 978-94-007-1165-5
Print ISBN: 978-94-007-1164-8
DOI: https://doi.org/10.1007/978-94-007-1165-5

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