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Advisor(s)
Abstract(s)
Pressure and temperature increase in combustion chambers of Liquid Rocket Engines (LRE’s), while
enhancing injection and combustion efficiencies, leads to both fuels and oxidizers to exceed their critical point
conditions, entering the domain of supercritical fluid flows. Over the past 20 years, many physical models are
developed for the simulation of supercritical nitrogen injection, which is validated with the experimental data
from [1] and [2]. However, regardless of the sophistication employed in RANS, LES [3] or DNS-based [4]
approaches, unrealistic top hat density profiles appear in the computations, which have in common the
consideration of adiabatic injector walls.
The present work has the objective of quantifying the influence of injector wall heat transfer for the considered
experimental conditions, contributing for a more accurate representation of the physical phenomena in LRE's
combustion chambers. For this purpose, a RANS-based approach is followed combining the accuracy of a
multiparameter equation of state for nitrogen with an incompressible, but variable density approach description
of the mixing conditions.Figure 1 depicts a comparison of the results obtained for the centerline density decay for case 4 from [1]. The
injector diameter normalizes the axial distance from the injector. In this figure, the origin corresponds to the
entrance of the combustion chamber. For the case of the adiabatic injector walls, it can be observed a potential
core until x/D = 7.5, as opposed to what is depicted in the same figure for the experimental data.
Experimentally no core is predicted, and the axial density starts to decrease as soon as the beginning of the
combustion chamber. If, on the other hand, the isothermal injector is considered, it can be seen that no top hat
profile appears, and the numerical results closely replicate the experimental behavior of the jet.It is shown that injector heat transfer phenomena actively changes the topology of the jet mixing, contributing to improved performance of numerical solvers.
Description
Keywords
Liquid Rocket Engines LRE Supercritical condition RANS-based approach Multiparameter equation of state Notycompressible, but variable density approach
Citation
Leandro Magalhães, André Silva, Jorge Barata, "Injector Wall Heat Transfer Quantification in Supercritical Nitrogen Injection", Space Propulsion 2020 Conference, Estoril, Portugal, 08-12 february, 2021
Publisher
Association Aéronautique et Astronautique de France