TABLE OF CONTENTS During the last decade, process machinery users have gradually become aware that the achievement of reliable, continuous operation of their machinery is perhaps the most important aspect affecting their decision to purchase a specific piece of equipment. As a result, there is more mention of the word "reliability" in equipment standards, and certain well-defined component lifetimes are now being specified. In earlier times parameters such as initial cost or higher efficiencies were the deciding factors in purchasing plant machinery. However, and as was brought out in our earlier chapters, the use of these "non-experience-based" decision-making methods led to the purchase of machinery which met all the project specifications at the time but resulted in unreliable, expensive to maintain plant equipment.
The design of a turbomachine has a direct influence on its life-cycle reliability and, therefore, its ability to operate with a maximum time interval between failures. A new mechanical reliability concept can shed light on what has so far been essentially a black art based partly on science and partly on experimental verification with little in the form of theory to guide the way. This concept involves creating a universal mechanical failure mode list that applies to all machinery and, from there, developing design rules and guidelines that eliminate these failure modes or isolate their effects. Applying these design principles leads to advanced turbomachinery that exhibits an extremely high resistance to mechanical breakdown.
