Experimental studies on structure of airblast spray in crossflow
- 75 Downloads
The present investigation is focused on experimental studies on the structure of airblast spray in crossflow. Atomizer is at a higher pressure than ambient and the airblast gas is expected to exhibit features generally found in under-expanded gas jets. High-speed images are captured using shadowgraphy technique. Certain wave-like structures observed in the near-nozzle region are attributed to shock–vortex interactions, generally observed in under-expanded gas jets. Proper Orthogonal Decomposition (POD) analysis has been carried out using these images. POD mode shapes clearly show signatures of shock–vortex oscillations and frequencies close to the screeching frequency observed in under-expanded jets. The POD modes are compared for different conditions and the significance of dynamic structures and their temporal behavior is discussed. Finally, a regime map is also proposed to characterize spray behavior in crossflow.
KeywordsSpray in crossflow Proper Orthogonal Decomposition (POD) under-expanded jet shock–vortex interaction shock-oscillation Mach disc screeching jet spray regimes
The authors thank for the financial support provided by the GATET programme of the Aeronautics Research & Development Board (ARDB), Government of India, for this work. The authors also thank Prof. Satya Chakraborty, and Dr. Ramgopal from IIT Madras for the help in POD analysis used in this study.
- 1.Lefebvre A H and Ballal D R 2010 Gas Turbine Combustion 3rd ed., CRC PressGoogle Scholar
- 6.Mazallon J, Dai Z and Faeth G M 1998 Aerodynamic primary breakup at the surface of nonturbulent round liquid jets in crossflow. AIAA Paper 716 Google Scholar
- 10.Sinha A, Prakash S R, Raghunandan and Ravikrishna R V 2013 Experimental investigation of jet dispersion in a cross flow. In: National Propulsion Conference, IIT Madras, India, Feb. 21–23Google Scholar
- 13.Leong M Y, McDonell V C and Samulesen S 2000 Mixing of an airblast atomized fuel spray injected into a crossflow of air, NASA/CR-2000-210467 Google Scholar
- 19.Roshko H W and Liepmann A 2007 Elements of Gasdynamics. Dover PublicationsGoogle Scholar
- 20.Donaldson C D and Snedeker R S 1971 A study of free jet impingement. Part 1. Mean properties of free and impinging jets. J. Fluid Mech. 45(2): 281–319Google Scholar
- 22.Sommerfeld M 1990 The influence of solid particles on the structure of supersonic free jet flows. In: AIP Conference Proceedings, AIP, vol. 208, No. 1, pp. 745–750Google Scholar
- 23.Sommerfeld M and Kurian J 1995 Droplet behaviour in underexpanded supersonic jets. In: Shock Waves at Marseille III. Springer, Berlin, Heidelberg, pp. 95–100Google Scholar
- 29.Manning T and Lele S 1998 Numerical simulations of shock–vortex interactions in supersonic jet screech. In: 36th AIAA Aerospace Sciences Meeting and Exhibit, p. 282Google Scholar
- 33.Spraying Systems 2018 Automatic and Air Atomizing Spray Nozzles. Product Catalogue, Spraying SystemsGoogle Scholar
- 36.Constantinos H 2014 Investigation of break-up process of liquids and downstream spray characteristics in air-blast atomisers. PhD dissertation, Imperial College, LondonGoogle Scholar