The severe vibration of a screw compressor outlet piping system caused the fatigue failure of some thermowells and the unscheduled shut down of the system. The main reasons of the abnormal vibration in the outlet piping system were investigated by developing an acoustic model to simulate the gas pulsation and establishing two finite element models to conduct the mechanical vibration analyses. T...

Improvement of compressor efficiency using the alternative refrigerant is demanded strongly to reduce CO2 emission, which causes the global warming. Especially the compressor using in frozen temperature level has long lifetime, and the correspondence to above-mentioned is one of the most important subjects. The scroll compressor is the promising structure to solve this problem. A technical poin...

A non-linear gas dynamic model is used in this paper to study the pressure pulsations in the intake of a variable speed compressor, since the perturbation pressure in this study is so large that the linear acoustic theory is no longer valid. Friction and heat transfer are considered in the model. Three numerical schemes are applied to solve the governing equations which are non-linear hyperboli...

The development of a series of sin~le-stage, oilfree screw air compressors with a compression ratio of 8, previously obtainable only with two-sta~e compressors, is described. A new rotor profile, which reduces leakage loss to achieve higher efficiency, and desig-ned for ease of manufacture, is detailed. Additionally, a new desig-n method for the clearance between rotors, to compensate for rotor...

The forced vibration of the 2D NASA flutter compressor cascade is numerically simulated in full scale with parallel computation technique. The compressor cascade consists of 9 blades bounded by 2 wind tunnel side walls. The implicit line Gauss-Seidel iteration with dual time stepping is employed. The turbulence is modeled with the Baldwin-Lomax model. A newly developed high resolution efficient...

Although wet (oil injected) and dry (oil free) screw compressors are widely used in many applications, limited information is available regarding the pulsation, vibration, and noise problems associated with these types of compressors. This tutorial discusses such problems and includes case histories where field testing was performed, and provides design recommendations. Both wet and dry screw c...

A plain journal bearing is spontaneously unstable above a critical speed and loses much of its load carrying capacity when subjected to a load rotating at about half the speed of the shaft. The almost axially symmetric flow in a compressor can break down at low flow into a rotating pattern of stall cells but only the special case of a single propagating stall cell gives rise to a mechanical cou...

An advanced warning system for maintenance and control of reciprocating compressors is discussed. The compressor is instrumented to measure valve temperatures, interstage pressures and temperatures, rod drops, packing temperature and leakage flow, and numerous other variables. Under control of a microcomputer, a scanner monitors the sensors and updates a database. After a scan, an expert progra...