The mixing-plane method for calculating the three-dimensional flow through multistage turbomachinery is used to perform flutter analysis on a single stage transonic compressor. The turbomachine considered is composed of an inlet guide vane (IGV) and a compressor blade (NASA Rotor 67). The mixing-plane boundary condition enables steady and unsteady computation of the flow through multiple blade ...

By making use of a suite of programs for designing profile geometry, cutter geometry and predicting the thermodynamic performance of a twin screw compressor, this paper investigates techniques of obtaining an optimised rotor cutter blade design. The techniques for using different geometric schemes for setting clearances are explained, and the techniques for optimising main manufacturing paramet...

Most scroll compressor models are based on a geometrical description of the scroll wraps. Since geometry is one of the main factors affecting the efficiency of the compressor, a complete description of the geometry of scroll wraps has to be known in order to establish an accurate thermodynamic model. Most authors do not yield an analytical expression of the discharge chamber, also because their...

During the process of refrigerant alternative, R290 (propane), as a nature refrigerant used in Room Air Condition (RAC) system, is thought as a long-team substance and has attracted great attention. This paper simply introduced the characteristics and standard demands of R290 application, then, based on a 1HP R290 DC INV. RAC system at first, then finished the comparison test when a one-cylinde...

This paper presents the development and validation of a simulation model of an injection scroll compressor that can be used for optimization of a heat pump system for electric vehicles. The modeling considered the effects of refrigerant leakage and suction gas heating. The simulation model solved continuity and energy conservation equations using 4th Runge-Kutta scheme to predict the pressure a...

Multiplication represents a fundamental building block in all DSP tasks. Due to the large latency inherent in multiplication, methods have been devised to minimize the delay. Two methods are common in current implementations: regular Arrays and Wallace trees. For higher order multiplications, a huge number of adders are to be used to perform the partial product addition. Reduction of adders by ...

The verbose nature of XML has been mulled over again and again and many compression techniques for XML data have been excogitated over the years. Some of the techniques incorporate support for querying the XML database in its compressed format while others have to be decompressed before they can be queried. XML compression in which querying is directly supported instantaneously with no compromi...

Computer Engineering Group Technical Report Electrical and Computer Engineering Department University of Toronto November 18, 2004 Abstract This work proposes a novel checkpoint store compression method for giga-scale, coarse-grain checkpoint/restore. This mechanism can be useful for debugging, post-mortem analysis and error-recovery. The effectiveness of our compression method lies in exploiti...

This paper deals with open-shaft twin-screw refrigeration compressors in the 10 175 m3/h (10 100 CFM) range. Applications for such compressors are, for example,external combustion engine heat-pumps and transport refrigeration. The twin-screw compressor concept is discussed from following view-points; operational mode and rotor housing design drive arrangement bearings lubricants cooling volume ...

The twin-screw compressor is constantly attaJ.ninq hiqher performance due to new rotor profiles, new rotor manufacturing technology and new designs. Besides this, new refrigerants as well as new lubricants can be expected on the market. Therefore there is always a need to update performance data. To m1nimize the number of test points and still receive representative data, there 1s a need of an ...