International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 08 Issue: 08 | Aug 2021 www.irjet.net p-ISSN: 2395-0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1010 Fatigue Modelling of Reed Valve as a Function of Crank Angle for Piston Compressor Onkar Sawant 1 , Pravin Mane 1 , Utsav Verma 2 1 Department of Mechanical Engineering, WCE Sangli, Sangli-416415, India 2 GECIA, Atlas Copco (India) Ltd, Pune-411057, India ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - Reciprocating compressors are used to deliver high-pressure gas. As the limiting elements in the design of the reciprocating compressor, the valves can be considered. These valves are heart of the compressor, after failure, it would lead to the shutdown of the compressor and to costly downtimes. A compressor running at even moderate speeds such as 700 rpm requires for each valve to open and close over one million times a day. Valve design be highly reliable and operate efficiently in adverse conditions, such as in applications where liquids, debris in gas stream. Among all cause of failure of reed valve, fatigue is being major reason. As reed valve acts as a vibrating system, it undergoes thousands of stress cycles within a minute; which causes fatigue failure. In this project, the reasons for fatigue failure are discussed. Also, the factors affecting fatigue failure of valve will be evaluated. Bending stress due to lift of valve will be considered for fatigue life calculation. The SN curve will be drawn to calculate fatigue life which will be used to evaluate life of valve. The natural frequency of valve will be calculated and finally fatigue stress will be related in terms of cack angle Key Words: fatigue life, reed valve, fatigue stress, Reciprocating compressors 1 INTRODUCTION Reciprocating compressors are one of the most commonly utilised type. They're utilised in a wide range of industries, including the oil and gas sector and the chemical industry, where they're primarily used for their capacity to deliver high-pressure gas. Because piston compressors are such an important aspect of any process in which they are used, their dependability has attracted a lot of attention. Figure -1: Reasons of compressor failure Each valve on a compressor having normal speed of around 800 rpm, must open and close over one million times every day. As a result, when designing a valve, keep in mind that it must be not fail i.e., should be reliable and perform effectively even under difficult conditions, such as when there are liquids or debris in the gas stream. Fatigue is one of the most common reasons for reed valve failure. Because the reed valve is a vibrating mechanism, it goes through thousands of stresses cycles each minute, resulting in fatigue failure. The reasons for fatigue failure, factors impacting valve fatigue failure, and eventually fatigue will be related in terms of cack angle in this project. 2 LITERATURE REVIEW In 1777, James Watt built a stream engine, which us used to run an air compressor. Although the use of air compressor getting popular, valve design was not included in literature. The early attempts to explain valve behavior, however, were solely empirical, despite the lack of experimental methods for recording valve activity, such as measuring lift as a function of time. Having [5] recorded change in design of valve from time to time. This type of evolution is shown in following Fig 2 Figure -2: Timeline of evolution of valve design methods Sittenfeld (1901) [6] published a book in which he attempts to solve valve properties using theoretical assumptions instead of empirical methods. The resultant model was simple as it was based purely on Newton's second rule and Bernoulli's equation for incompressible fluid. Hirsh (1932) [7] published a book in in which he acknowledged the complexities of the physical condition involving valve function, which is influenced by a multitude of circumstances. Later that year, Lanzendörfer [8] used a mechanical (pressure) indicator to measure valve displacement in a running compressor.