The effect of cavitation on the estimation of fuel injection rates based on momentum flux measurements

Abstract. Direct measurements of the turbulent air–sea fluxes of momentum, heat, moisture and gases. are often made using sensors mounted on ships. Ship-based turbulent wind measurements are corrected for platform motion using well established techniques, but biases at scales associated with wave and platform motion are often still apparent in the flux measurements. It has been uncertain whether this signal is due to time-varying distortion of the air flow over the platform, or to wind–wave interactions impacting the turbulence. Methods for removing such motion-scale biases from scalar measurements have previously been published but their application to momentum flux measurements remains controversial. Here we show that the measured motion-scale bias has a dependence on the horizontal ship velocity, and that a correction for it reduces the dependence of the measured momentum flux on the orientation of the ship to the wind. We conclude that the bias is due to experimental error, and that time-varying motion-dependent flow distortion is the likely source.

Download Full-text

Drake Antarctic Agile Meteor Radar first results: Configuration and comparison of mean and tidal wind and gravity wave momentum flux measurements with Southern Argentina Agile Meteor Radar

Journal of Geophysical Research Atmospheres ◽

10.1029/2011jd016651 ◽

2012 ◽

Vol 117 (D2) ◽

pp. n/a-n/a ◽

Cited By ~ 28

Author(s):

D. C. Fritts ◽

D. Janches ◽

H. Iimura ◽

W. K. Hocking ◽

J. V. Bageston ◽

...

Keyword(s):

Gravity Wave ◽

Momentum Flux ◽

Meteor Radar ◽

First Results ◽

Flux Measurements ◽

Wave Momentum

Download Full-text

Liquid Fuel Placement and Mixing of Generic Aeroengine Premix Module at Different Operating Conditions

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1587741 ◽

2003 ◽

Vol 125 (4) ◽

pp. 901-908 ◽

Cited By ~ 11

Author(s):

J. Becker ◽

C. Hassa

Keyword(s):

Momentum Flux ◽

Liquid Fuel ◽

Fuel Injection ◽

Measurement Techniques ◽

Flux Ratio ◽

Mie Scattering ◽

Operating Conditions ◽

Operating Pressure ◽

Flow Measurements ◽

Momentum Flux Ratio

Fuel placement and air-fuel mixing in a generic aeroengine premix module employing plain jet liquid fuel injection into a counter-swirling double-annular crossflow were investigated at different values of air inlet pressure (6 bar, 700 K and 12 bar, 700 K) and liquid-to-air momentum flux ratio, both parameters being a function of engine power. Kerosene Jet A-1 was used as liquid fuel. Measurement techniques included LDA for investigation of the airflow and Mie-scattering laser light sheets and PDA for investigation of the two-phase flow. Measurements were taken at various axial distances from the fuel nozzle equivalent to mean residence times of up to 0.47 ms. It was found that the initial fuel placement reacts very sensitively to a variation of liquid-to-air momentum flux ratio. Susceptibility of the spray to dispersion due to centrifugal forces and to turbulent mixing is primarily a function of the fuel droplet diameters, which in turn depend on operating pressure. The data are interpreted by evaluation of the corresponding Stokes numbers.

Download Full-text

Liquid Fuel Placement and Mixing of a Generic Aeroengine Premix Module at Different Operating Conditions

Volume 1: Turbo Expo 2002 ◽

10.1115/gt2002-30102 ◽

2002 ◽

Author(s):

Julian Becker ◽

Christoph Hassa

Keyword(s):

Momentum Flux ◽

Liquid Fuel ◽

Fuel Injection ◽

Measurement Techniques ◽

Flux Ratio ◽

Mie Scattering ◽

Operating Conditions ◽

Operating Pressure ◽

Flow Measurements ◽

Momentum Flux Ratio

Fuel placement and air-fuel mixing in a generic aeroengine premix module employing plain jet liquid fuel injection into a counter-swirling double-annular crossflow were investigated at different values of air inlet pressure (6 bar, 700 K and 12 bar, 700 K) and liquid-to-air momentum flux ratio, both parameters being a function of engine power. Kerosene Jet A-1 was used as liquid fuel. Measurement techniques included LDA for investigation of the airflow and Mie-scattering laser light sheets and PDA for investigation of the two-phase flow. Measurements were taken at various axial distances from the fuel nozzle equivalent to mean residence times of up to 0.47 ms. It was found that the initial fuel placement reacts very sensitively to a variation of liquid-to-air momentum flux ratio. Susceptibility of the spray to dispersion due to centrifugal forces and to turbulent mixing is primarily a function of the fuel droplet diameters, which in turn depend on operating pressure. The data are interpreted by evaluation of the corresponding Stokes numbers.

Download Full-text