A Deceleration Probe for Measuring Stagnation Pressure and Velocity of a Particle-Laden Gas Stream

Dussourd, J. L.; Shapiro, Ascher H.

doi:10.2514/8.7216

Cited by 19 publications

(3 citation statements)

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“…In (2), it is shown that the shape of a particle trajectory subjected to the two-or three-dimensional flow field around a body of diameter D is governed by 3 p 1 D the quantity C D4 psd where C D is the particle drag coefficient, herein assumed to be expressed as C = constant = constant (A-1) D7 pg over the Reynolds Number range of interest. We will designate…”

Section: Appendixmentioning

confidence: 99%

A Simple One-Dimensional Model for Primary Turbine Blade Erosion Prediction

Dussourd

1983

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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Sophisticated models to predict the erosion process in turbine blades exposed to dust laden gas stream quickly become complex and tedious for use for everyday engineering applications. A simpler model for primary erosion can be formulated by assimilating the blade row to a device having a certain size and deflecting the stream through a given angle and at a given rate. The technology which exists for particle impacts physics with bluff bodies can be adapted to cascades. Thus, basically the model is derived from first principles. This approach is formulated in a quantitative manner in terms of cascade parameters, gas properties, and particulate parameters. The result is a simple equation which is easy to use and the physics of which are logical and intuitively reasonable. Its predictive ability, however, is limited to the frequency of impacts and the strength of the impacts. It does not address the mechanics of the impact process or the properties of the material being impacted. These variables are introduced through an experimental coefficient which, as it turns out, is the only experimental input in the analysis. The method is tested against quite a few experimental cases with a degree of predictive ability which is acceptable in a simple, first order method. The agreement is thought to be at least as good as the credibility or accuracy of the test data. The method is finally applied to study the effects of various blade cascade parameters on erosion resistance, the results of which are presented in the form of general curves.

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Section: Appendixmentioning

confidence: 99%

A Simple One-Dimensional Model for Primary Turbine Blade Erosion Prediction

Dussourd

1983

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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“…However, no practical method was suggested for determining the true velocity from the recorded pressures. Crane & Moore (1972) improved upon the theory of Dussourd & Shapiro (1958) and presented calculations for the flow of wet steam around purged or unpurged Pitot tubes. They determined the vapour velocity field around the Pitot tube by means of an incompressible, potential flow theory and assumed that the same velocity field applies in the presence of the droplets as well.…”

Section: Introductionmentioning

confidence: 99%

A unified theory for the interpretation of total pressure and temperature in two-phase flows at subsonic and supersonic speeds

Guha

1998

Proc. R. Soc. Lond. A

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This paper presents a unified theory on the interpretation of total pressure and total temperature in multiphase flows. The present approach applies to both vapourdroplet mixtures and solid-particle laden gases, and at subsonic as well as supersonic velocities. It is shown here that the non-equilibrium processes occurring in the vicinity of a stagnation point are important. These processes may be responsible for the generation of entropy and affect the pressure and temperature at the stagnation point. They should be properly considered while inferring, say, flow velocity or entropy generation from Pitot measurements. By proper non-dimensionalization of the relevant parameters, it is possible to find a single (theoretically obtained) calibration curve for the total pressure as a function of the particle size, which is almost independent of the constituents of the multiphase mixture and of the flow conditions. The calibration curve is a plot of a pressure recovery factor versus Stokes number and specifies the total pressure under different non-equilibrium conditions. The total pressure, predicted by the present theory, varies monotonically between the two limiting values: the frozen total pressure (when there is no interphase mass, momentum and energy transfer in the decelerating flow towards the stagnation point) and the equilibrium total pressure (when the dispersed phase, either the liquid droplets or the solid particles, is always at inertial and thermodynamic equilibrium with the continuous vapour phase). The equilibrium total pressure is always higher than the frozen total pressure. It is shown that the equilibrium total temperature, on the other hand, may be higher or lower than the frozen total temperature. In addition, unlike the case of total pressure, the calibration curve for total temperature is not so universal, and the total temperature under non-equilibrium conditions is not necessarily bounded between the frozen and equilibrium values. It is further shown that the entropy of a multiphase mixture has to be carefully interpreted and is not unequivocally related to the total pressure even in steady adiabatic flow.

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“…Reproducible results and good response to flow transients were obtained over several months operation. Pitot tubes have also been used by Anderson and Mantzouranis (1960), Adorni et al (1961), Gill et al (1963), Delhaye (1966), andDzakowic andDix (1969) to investigate steady gas-liquid flow and by Dussourd and Shapiro (1955) and Dalnion and Lowe (1957) for gas-solid flow. Generally, reasonable agreement with input flow was obtained by integrating the total phase flow across the channel.…”

mentioning

confidence: 99%