Discharge Coefficients and Heat Transfer for Axisymmetric Supersonic Nozzles
Titel:
Discharge Coefficients and Heat Transfer for Axisymmetric Supersonic Nozzles
Auteur:
Ahmad, Rashid A.
Verschenen in:
Heat transfer engineering
Paginering:
Jaargang 22 (2001) nr. 6 pagina's 40-61
Jaar:
2001-11-01
Inhoud:
Computational fluid dynamics (CFD) analysis was used to compute effective nozzle discharge coefficients for subscale sharp-edged converging/diverging nozzles, with a variety of convergence half-angles, motor operating conditions, and two propellants with different ballistics. Convergence half-angles ranged from 10° to 90°. Analysis was conducted at total temperatures from 2,946 K (5303°R) to 3,346 K (6023°R) and total pressures ranging from 2.72 MPa (395 psia) to 20.68 MPa (3,000 psia). Area ratios (A e /A*) ranged from 7.43 to 9.39. Ratio of specific heats ( γ) ranged from 1.13 to 1.18. The maximum throat and exit Reynolds' numbers based on axial diameter ranged from 6.73 ×105 to 3.61 ×106 and 3.26 ×105 to 1.99 ×106, respectively. Present results of nozzle discharge coefficients are reported and correlated as a function of nozzle convergence half-angle ( θc ), area ratios (A e /A*), and pressure ratio (P o /P ∞) for a constant divergence half-angle ( θd ) of 15°. Computed discharge coefficients ranged from 0.88 to 0.97. They are compared with theory and experimental data available in the literature. Available turbulence models with respect to grid refinements and heat transfer are discussed. Heat transfer is calculated from a modified Reynolds' analogy for laminar flow over a flat plate, the Dittus - Boelter correlation for fully developed turbulent pipe flow, and the Bartz correlation for nozzle flows, and the results are compared with available experimental data.
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