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Mixing Analysis of Like Doublet Injectors in High Pressure Environments for Gelled Propellant Simulants

Notaro, Vincent
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406821648

Abstract Details

2014, MS, University of Cincinnati, Engineering and Applied Science: Aerospace Engineering.
Impinging doublet injectors offer rocket designers an effective way to atomize and mix opposing jets of fuel and oxidizer. The adaptability of the injector designs and ease of manufacturing make them attractive choices for designers. The adaptability of injector designs introduces many variables to the system like orifice diameter, nozzle orifice pairings, and working fluid to name a few. This expanse of variables requires characterization of phenomenon produced and measurement of performance. The characterization of phenomenon can be used to help explain performance. The atomization and spray characteristics of impinging jets are well understood. The studies in this field cover a multitude of design variables. While mixing quantification is well understood for liquid working fluids and similar orifice pairings, data are still lacking on non-Newtonian working fluids, specifically gelled simulants, and dissimilar orifice pairings. In addition, like mixing data exists for sprays in elevated ambient pressure conditions. Gelling of propellants provides advantages of easier handling and less vapor issues as compared to liquid propellants. Dissimilar orifice pairs offer the opportunity to achieve desired mixture ratios without largely varying operating conditions. A review of mixing studies for liquid working fluids is conducted. The studies focus on defining mixing efficiencies changes based on the injector design variables. In addition, some mixing mechanisms are established and discussed phenomenologically. A review of atomization studies is also conducted. These studies help shed light on mixing characteristics as well as help progress diagnostics in the mixing study field. These studies also focus injector design variables but cover more variables in greater depth than the mixing studies. A combination of a pressure chamber, two flow systems for the two different working fluids, and two pairings of nozzles is used to characterize mixing over different injection velocities and ambient conditions. In addition, the two working fluids and two different nozzle pairings allow comparisons to be made between the different cases. The injection velocity conditions range from 8 m/s to 20 m/s in ambient pressure conditions from atmospheric to 500 psi. Mixing efficiency is calculated using spray mass distributions acquired by PLIF technique. The data processing procedure is defined and is applicable to similar data acquisition systems. The mixing data acquired show that for similar orifice diameter impingement, the ambient pressure increase above atmospheric enhances mixing for both gelled and non-gelled fluid due to reduced break-up lengths. However, the mixing efficiency stops increasing and remains constant above a certain ambient pressure. Gelled simulant generally results in poorer mixing efficiencies than the non-gelled simulant, suggesting momentum carried and pre-impingement jet conditions are the determining factors in mixing. For dissimilar orifice diameter impingement, mixing is generally constant over all the ambient pressures including atmospheric. This may be due to the far downstream distance collection location. For optimized operating conditions, the dissimilar orifice-diameter impingement case can produce better mixing than the similar orifice diameter impingement case.
Jongguen Lee, Ph.D. (Committee Chair)
San-Mou Jeng, Ph.D. (Committee Member)
Milind Jog, Ph.D. (Committee Member)
75 p.
Aerospace Materials
doublet injector; impinging jet; mixing efficiency; hypergolic; gelled simulant; ambient pressure

Recommended Citations

Citations

  • Notaro, V. (2014). Mixing Analysis of Like Doublet Injectors in High Pressure Environments for Gelled Propellant Simulants [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406821648

    APA Style (7th edition)

  • Notaro, Vincent. Mixing Analysis of Like Doublet Injectors in High Pressure Environments for Gelled Propellant Simulants. 2014. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406821648.

    MLA Style (8th edition)

  • Notaro, Vincent. "Mixing Analysis of Like Doublet Injectors in High Pressure Environments for Gelled Propellant Simulants." Master's thesis, University of Cincinnati, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406821648

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Cincinnati and OhioLINK.