A miniature homogenous charge compression ignition (HCCI) free-piston engine compressor aimed at an ankle-foot orthosis application is described. Analysis of the human ankle shows that a fluid power source in the neighborhood of 10 W is needed. To account for compressor and actuator inefficiencies, the power output at the engine cylinder is designed to be 30 W. A compact engine compressor packa...

T he increase of the thrust-to-weight ratio of modern gas-turbine engines results in higher loads and a reduced number of blades and stages for the compressor. The designer must ensure the acceptable performance of each compressor stage (efficiency and stable operating range) and control the rising risk of blade boundary layer separation. This can be obtained using passive or active control dev...

An analytical study was carried out to investigate the performance of an oil supplying system of a variable speed compressor using a commercial CFD program. The simulations for the oil supplying system with the oil and air mixture were performed by varying compressor speed from 40 Hz to 90 Hz. Comparing the predicted with the measured data on the modified scroll compressor validated the simulat...

Supervision of the performance of an industrial gas turbine is important since it gives valuable information of the process health and makes efficient determination of compressor wash intervals possible. Slowly varying sensor faults can easily be misinterpreted as performance degradations and result in an unnecessary compressor wash. Here, a diagnostic algorithm is carefully combined with non-l...

A compressor is an automatic gain control effect that scales the output level of a signal based on the input level. If the input level is above a certain threshold, the compressor reduces the gain of the signal based on how high the input signal is above the threshold. The 1176LN is a hardware compressor originally produced in the late sixties. The circuitry has been tweaked several times to de...

This study involves the development of a fmite element model of a hennetic reciprocating compressor for noise prediction applications. Inherent difficulties in developing the finite element model of a complicated structure are discussed and appropriate modeling strategies are evolved. The development of the complete compressor fmite element model is carried out in two stages modeling of the com...

This pape,r describes a flow-visualizatio n technique that was employed to qualitatively evaluate the gas flow pattern inside a small, low side, hermetically sealed, re ciprocating refrigeration compressor. The applicable compressor des igns are those in which the suction gas from the evaporator is dumped into the compressor shell, and is then drawn through a muffler into the suction plenum of ...

This paper presents the construcrion, newly developed design technologies and performance characteristics of a compact horizontal scroll-type compressor for room air conditione~:s. The authors were able lo develop a compacl variable speed horizontal scroll-type compressor with a cooling capacity of I. 8 kW, which necessitated the development of new mechanisms, namely, an alCial compliance mecha...

This paper introduces the high efficiency of a horizontal rolling piston type compressor for household refrigerators. In the rolling piston type compressor, excessive compression loss and leakage loss largely affects the efficiency of the compressor. An experimental analysis of the following three items was made to determine that the performance characteristics of the compressor could be improv...

In this paper, the transient model of a water-cooled centrifugal chiller is developed in Modelica with Dymola and the TLK/IfT Library (TIL). The centrifugal compressor is modeled in detail based on the turbomachinery theory. The chiller capacity control is achieved by the combination of variable inlet guide vane (VIGV) and variable speed drive (VSD). The shell-and-tube heat exchangers are discr...