As refrigeration compressor manufacturers introduce machineswith improved efficiencies there is a need for updatingperformance data.The compressor performance data which is published should bea true representation of the actual compressor performance,historically this has resulted in lengthy test programmes for thecompressor manufacturer. A system is required which c...

A novel method for introducing a back-up system to an active compressor surge control system is presented in this paper. Active surge control is a promising method for extending the compressor map towards and into the unstable area at low mass flow by stabilizing the surge phenomenon. The method also has potential for allowing operation at higher efficiencies. However, a failure in the active s...

We describe an effective numerical approach to solving nonlinear 2 or optimal control problems. Our principal goal will be to use this approach to solve the important problem of jet engine compressor control. The technique is demonstrated first with the tutorial example of the control of a pendulum. We then apply the numerical approach to the problem of controlling jet engine compressor stall a...

Centrifugal compressors are used in a large number of different compression applications. This tutorial addresses applications for centrifugal compressors in the upstream and midstream sector, such as LNG compression, refrigeration, pipeline compression, compression for gas injection, gas lift, gas gathering, export compression, air compression, and others. The focus is on the specific compress...

The adjustment and control mode of frequency conversion for an air-conditioner can make the refrigeration capacity adapt the variety of its load very well. Thus, it has many advantages such as low variety in in-door temperature, short time to reach the wished temperature, low energy consumption, low start electric current and low strike to electric source etc. This mode is widely used in room a...

If compressor manifolds are thin compared to the shortest wavel~ngth of i:r:tt~rest, the gene!al procedure developed by the authors [1, 2] for the analysis of curved, t~l? gas cav1hes can be apphed to the analysis of gas pulsations in multi-cylinder compres~?r head cav1t1es. The procedure for smgle input single output systems is extended to systems of multl-mputs. Four pole parameters and trans...

INTRODUCTION Investigators conducted a prospective experimental study to evaluate the effect of team size and recovery exercises on individual providers' compression quality and exertion. Investigators hypothesized that 1) larger teams would perform higher quality compressions with less exertion per provider when compared to smaller teams; and 2) brief stretching and breathing exercises during ...

We present dewar temperature and system temperature measurements for the eight cryogenically cooled receivers of a subset of four EVLA antennas that have undergone a reconfiguration to use three cryogenic compressors instead of four. We compare the changes in the system temperatures in these antennas with those obtained from a subset of eight other EVLA antennas that have not undergone such a r...

In accordance with worldwide consensus, the use of chlorofluorocarbons, which play an important role in damaging the ozone layer, should be completely abolished by the end of 1995. This provided the impetus for developing the three vane rotary compressor. Formerly CFC-12 was used as the refrigerant in automotive air conditioners, until HFC-134a was substituted for CFC-12. In response to the cha...

Variable inlet guide vanes (VIGVs) are widely used for flow throttling and also extending the operating range of centrifugal compressors. Although there several studies on effects adding IGVs performance curve compressors, none them have focused number vanes. In current study, high-fidelity three-dimensional numerical simulations carried out to analyze VIGVs with different aerodynamic a single-...