Accurate animation of the thermo‐fluidic performance of the pressure‐wave machine and its balanced material operation

Abstract

Accurate animation of the thermo-fluidic performance of the pressure-wave machine and its balanced material operation H. OberhemH.A. Nour Eldin Article information:To cite this document: H. OberhemH. A. Nour Eldin, (1995),"Accurate animation of the thermo-fluidic performance of the pressure-wave machine and its balanced material operation"If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. ABSTRACTModelling, computation and performance animation of turbomachinery systems has recently enjoyed remarkable attention in CAD research. This is also reflected its application to exhaust machine components such as turbo loaders and the exceptionally novel pressure wave machine (Comprex) in the automobile industry and gas turbines. The necessity for the thermo-fluidic performance animation of such pressure wave machines results from the fact that the machine geometry must be adapted to the technical and thermo-fluidic properties of the exhaust flow of the gas turbine or automobile engine. Experimental adaptation or adjustment is costly and should be validated for every application case. Thus the potential to apply accurate animation for such shock-tube like behaviour of compressible flow is now economically promising with a view to optimizing the design of the pressure wave machine. This paper presents briefly the problem oriented algorithms used and illustrates the performance animation of the pressure wave machine operating under constant speed drive. After introducing the pressure wave machine operation, the principles and summary of the algorithms used to compute the thermodynamic behaviour within the cell, the boundary models and the accuracy of computation. A Comprex cycle operating on an engine exhaust gas with T= 920°K, p = 2bar is illustrated through 3-dimensional representations for pressure, speed of flow and temperature. The particle path (gas and air) together with time representation of the state variables at different points of the Compex will be shown. The mass balance problem is discussed and the conditions for mass balanced flow for the gas as well as for the air side are given. The results achieved for such materially balanced pressure wave machines indicate a reduction in the costs for subsequent experimental validation and to ...

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“…As the shock wave reaches the end of the channel, the outlet port is opened and the compressed air is then pushed through the outlet port 2 into the duct leading to the combustion chamber. This is usually called the tuning condition for the primary shock wave [20,21,26,27]. In the following it is referred to as tuning condition 1 (TC 1).…”

“…W 3 and W 2′ are the inlet and outlet port width, respectively. When the expansion wave reaches to the end of the channel, the entire flow inside the channel is halted, the outlet port is closed [20,21,26,27]. Here this is called tuning condition 3 (TC 3).…”

“…Here a favorite case is considered, where the closure of the gas inlet port is timed with the arrival of the secondary shock wave. This is called the tuning condition 2 (TC 2) [20,26,27]. This way, all the fluid column in the channel is compressed by the secondary shock allowing more gas to enter the channel.…”