Mechanical analysis of key components and machine performance for the oil regeneration project compressor
Special scroll profiles among the functional general scroll profiles were chosen to make a study on the integrative performance of the scroll compressor. Based on such profiles, it was further researched for all factors working on the integrative performance of the scroll compressor and the analysis of gas power was made on the key components influencing the integrative performance and four basic parameters including height, spindle rotation, involute angle and radius parameter of base circle. It was analyzed that the relation of axial gas power, radial gas power tangential gas power, overturning torque and rotation torque of dynamic and static vortex plate by employing the Genetic Algorithms (GA) of MATLAB to obtain the restricted parameter range, and to conclude that there is a linear relationship among four basic parameters and the overall force. Instance calculation was conducted to prove the validity of the restricted range that compression ratio and volume utilization have been increased greatly after optimization, so as to avoid the blindness of parameter selection and consequently improve the integrative performance of the scroll compressor.
Development of High Efficiency Scroll Compressors, for Air Conditioners
Recently, a scroll compressor for air conditioners has been developed, because of its high efficiency, quiet operation, light weight and small size. To accomplish high efficiency, self sealing mechanisms such as a tip seal and a swing link mechanism are very effective. Tip seals which are placed on the top of scroll wraps achieve thrust sealing and a swing link mechanism achieves radial sealing for compressed gas leakage. M.H.I. has been studying and developed high efficiency hermetic scroll compressors with tip seals and swing link mechanism. This paper presents as follows. (1) Experimental and computer simulation loss analysis (P-V diagram) were taken on wide speed range. Measured and calculated results were good agreement. (2) Orbiting scroll motion, tip seal motion and pressure distribution in seal groove were measured. Swing link motion was measured, too. As a result, it was comfirmed that self sealing for thrust and radial clearance were accomplished well. INTRODUCTION As for the recent heat pump air conditioners, compressors are required to operate in a wide speed range by means of inverter drive and in a wide operating pressure range. From the points of high efficiency, high reliability and the others, scroll compressors have been used. It is necessary to make a loss analysis in order to accomplish high efficiency of com-
Turbulent boundary layer wall‐pressure fluctuations downstream from an abrupt change in surface roughness
Spectra of wall‐pressure fluctuations beneath a turbulent boundary layer have been investigated immediately downstream from an abrupt change in surface roughness, from slightly rough to very rough. Over the measurable frequency band (400 Hz to 7 kHz), the spectra in the first 150 mm scale on wall variables. This indicates that the motions responsible for the pressure fluctuations measured in this region are very close to the wall. Farther downstream this scaling procedure breaks down. It is suggested that the initially thin internal layer behaves independently of the flow external to it until it has grown appreciably and only then interacts with the outer boundary layer. It was found that, for all frequencies measured, the dimensional spectral level decreases initially then rises to a maximum at 250 mm from the roughness change before decreasing once more. The position of the maximum is close to where the internal layer ceases to have a distinct edge.