Review of Compressible Pulsating Flow Effects on System Performance

Abstract

Pulsating flow is as old as the human being. It appears in different forms from a compressible to incompressible, one phase, two or multi phase flows. Some forms of pulsating flow are favorable like that increase the combustion efficiency in combustors. Other forms of pulsating flow are harmful such as pulsation associated with compressor surge leading to increase of the noise level. Understanding the behavior of the pulsating flow in different forms, its effects on the flow system performance and on the gas turbine engine cooling system are reviewed. Reynolds number, velocity gradient, pressure gradient and frequency are the main parameters that affecting the pulsating flow behavior. The measurement of pulsating flow in its forms is one of the major tasks of the researchers. From the review it appears that number of researches tried to cover the whole sides of pulsating flow phenomena and the different ways to measure it. However, a lot of works is still needed to be understood thoroughly the effect of pulsating flow on the flow systems and how it could be used to developed the performance.

Dynamic characteristics of orifice flowmeter impulse response based on CFD simulation

“…In recent years, there are many domestic and international studies on the dynamic performance of impulse response of orifice flowmeter. As early as the 1820s, researchers described pulsating flows and showed the difficulty of measuring them accurately [3] . The response of orifice flowmeters and venturi nozzle flowmeter in pulsating flows was studied by Mottram et al [4] .…”

The Resulting Effect of Flow Pulsations on Calibration Constant of Acoustic Path in Ultrasonic Flowmeters

“…The flow rate of a continuous medium in a pulsating flow was measured by almost all types of existing flowmeters: Venturi [ 28 ], Pitot tube [ 28 , 29 ], with a film element [ 28 ], vortex [ 1 , 28 ], turbine [ 28 , 30 , 31 ], current meters ([ 32 ] Jepson 1967), differential [ 27 , 33 ], and cross-correlation [ 1 ]. Generalization of these results (but only based on the pulsating flow regimes investigated by the authors) allows drawing the following conclusion: the measurement uncertainty increases significantly with an increase in the relative amplitude of pulsations, and to a greater extent this is aggravated in the designs of flowmeters with elements in contact with the pulsating flow [ 34 ]. For example, a turbine flowmeter responds more quickly to an increase in flow rate than to a decrease, which leads to an overestimation of the average flow [ 30 ], especially when measuring gas flow rates [ 31 ].…”

Estudo experimental do fenômeno de onda em coletores de admissão para motores de combustão interna

“…Tendo em vista os fenômenos e necessidades apresentadas acima, fica claro que deve haver uma preocupação em particular com o escoamento dinâmico ou pulsado nos Coletores de Admissão, isso é evidenciado com o crescente número de estudos encontrados sobre esse assunto, especificamente como os de Hanriot (2001), Persoons (2004), Guimarães (2008), Pereira (2008), Metwally (2009), Souza (2010), Oliveira (2011) e Queiroz (2011).…”

“…Pela definição de Metwally (2009), o escoamento de ar durante o processo de admissão de um motor de combustão interna é um tipo particular e não permanente, ocorrendo uma variação cíclica da velocidade, sobreposta a uma média temporal constante de vazão. Segundo o mesmo O afirmado acima fica mais claro em uma análise da Figura 2.5, que mostra a eficiência volumétrica de um dado Motor de Combustão Interna em função da rotação do mesmo para vários comprimentos de condutos.…”