Performance of a Titan Rocket Engine Using Laser-Induced Fluorescence of OH
2001; American Institute of Aeronautics and Astronautics; Volume: 39; Issue: 10 Linguagem: Inglês
10.2514/2.1182
ISSN1533-385X
AutoresL. M. Cohen, D. M. Jassowski, Jotaro Ito,
Tópico(s)Spectroscopy and Laser Applications
ResumoRocket engine performance can be modeled by considering separately the propellant delivery system distribution, combustion efe ciency including propellant vaporization and gas-phase mixing, and nozzle expansion efe ciency. Although these quantities can be modeled, experimental verie cation is extremely helpful for separately understanding these processes and for design improvements. Laser-induced e uorescence of OH, excited by a KrF excimer laser operating at 248 nm, is used to measure the concentration of the OH radical across the exit plane of a e ring Titan IV, stage I, liquid rocket engine, from which the combusting mixture ratio proe le could be inferred. Thesemeasurementsallowassessmentofthedegreeofmixing and potential e owstratie cationbetween theinjector core, combustion bafe es, and combustion chamber fuel-e lm cooling and can help to provide the basis for future performance optimization. Nomenclature A = Einstein A coefecient Aa = area of the laser beam (height times thickness ) B12 = Einstein second coefe cient for stimulated absorption c = speed of light E = laser energy per pulse fB.T/ = temperature-dependent Boltzmann fraction of the absorbing state g.o/ = spectral overlap function ho = energy of a scattered photon K = non-noise-free gain factor M = magnie cation of the imaging system Nc = number of counts recorded by the camera per pixel Np = number of laser pulses integrated NT = total number density of the gas Pc = rocket engine combustion chamber pressure Qpre = predissociation rate S = e uorescence signal T = gas temperature uradial = radial component of the velocity V = collection volume ´ = collection efe ciency ÂOH = mole fraction of OH A = collection solid angle per pixel ! = wave number of the laser Subscript pp = per pixel
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