The Thermodynamic and Fluid Dynamic Functions of a Pulsed Detonation Engine Nozzle

Kaemming, Thomas A.; Dyer, R.

doi:10.2514/6.2004-3916

Cited by 17 publications

(5 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8,9 However, in the case of a PDRE system fitted with a CD nozzle, the use of a relatively small nozzle throat (to help limit refill velocity and maintain chamber pressure) may enable multicycle performance near this ideal. 17,46 Conclusions A quasi-one-dimensional, finite rate chemistry CFD model for studying PDRE gasdynamics and performance is described and implemented. The single-pulse performance and blowdown time characteristics of four different PDRE geometries are studied over a range of blowdown pressure ratios from 1-1000.…”

Section: Equivalent Ssre Model and Performance Comparisonmentioning

confidence: 99%

Numerical Modeling of Single-Pulse Gasdynamics and Performance of Pulse Detonation Rocket Engines

Morris

2005

Journal of Propulsion and Power

View full text Add to dashboard Cite

Pulse detonation rocket engines (PDREs) offer potential performance improvements over conventional designs but represent a challenging modeling task. A quasi-one-dimensional, finite rate chemistry computational fluid dynamics model for PDREs is described and implemented. Four different PDRE geometries are evaluated in this work: a baseline detonation tube, a detonation tube with a straight extension, and a detonation tube with two types of converging/diverging (CD) nozzles. The effect of extension length and CD nozzle area ratio on the single-pulse gasdynamics and performance of a PDRE is studied over a wide range of blowdown pressure ratios (1-1000).The results indicate that a CD nozzle is generally more effective than a straight extension in improving PDRE performance, particularly at higher pressure ratios. Additionally, the results show that the blowdown process of the CD nozzle systems could be beneficially cut off well before the pressure at the endwall reaches the ambient value. The single-pulse performance results are also compared to some recent experimental measurements as well as a steady-state rocket system using similar modeling assumptions. Nomenclature= activation energy in Arrhenius relation e = specific internal energy F = Troe correction factor for pressure-dependent reactions F c = Troe centering parameter for pressure-dependent reactions F = inviscid convective flux vector H = source vector for area change I sp = specific impulse J = Jacobian of W with respect to U k b = backward reaction rate k eq = equilibrium constant k f = forward reaction rate k ∞ = high-pressure rate limit of pressure-dependent reactions k 0 = low-pressure rate limit of pressure-dependent reactions L = length M = molecular mass N r = number of reactions N s = number of species P r = reduced pressure for pressure-dependent reactions p = gas pressure R = universal gas constant S(x) = cross-sectional area as a function of x T = gas temperature t = time from detonation initiation t b = blowdown time; point in blowdown history when p w = p a t z = point in blowdown history when thrust first drops to zero U = wave velocity in the x direction U = state vector u = gas velocity in the x direction V = volume W = source vector for finite rate chemistry w = source term for finite rate chemistry x = distance from endwall Y = mass fraction β = temperature exponent in Arrhenius relation γ = ratio of specific heats f h = heat of formation ε = nozzle area expansion ratio, S x /S * ν = stoichiometric coefficient in chemical reaction ρ = gas density υ = volume ratio ψ = blowdown pressure ratio, p i / p a Subscripts a = ambient condition CJ = Chapman-Jouguet state c = pertaining to the converging section of a nozzle d = pertaining to the diverging section of a nozzle e = pertaining to a straight tube extension i = initial fill condition in the detonation tube j = reaction index k, l = species indices m = subiteration counter in predictor-corrector integration scheme t = pertaining to the detonation tube w = condition at the endwall of the d...

show abstract

Section: Equivalent Ssre Model and Performance Comparisonmentioning

confidence: 99%

Numerical Modeling of Single-Pulse Gasdynamics and Performance of Pulse Detonation Rocket Engines

Morris

2005

Journal of Propulsion and Power

View full text Add to dashboard Cite

show abstract

“…The Mach number in ( 9) is determined by using (1). As given in (10), the cross-sectional area A i (t) is determined by a one-sided scheme at the endpoints and a centred scheme about the point x i (t).…”

Section: Geometrical Shock Dynamics (Gsd)mentioning

confidence: 99%

Numerical and experimental evaluation of shock dividers

et al. 2022

View full text Add to dashboard Cite

Mitigation of pressure pulsations in the exhaust of a pulse detonation combustor is crucial for operation with a downstream turbine. For this purpose, a device termed the shock divider is designed and investigated. The intention of the divider is to split the leading shock wave into two weaker waves that propagate along separated ducts with different cross sections, allowing the shock waves to travel with different velocities along different paths. The separated shock waves redistribute the energy of the incident shock wave. The shock dynamics inside the divider are investigated using numerical simulations. A second-order dimensional split finite volume MUSCL-scheme is used to solve the compressible Euler equations. Furthermore, low-cost simulations are performed using geometrical shock dynamics to predict the shock wave propagation inside the divider. The numerical simulations are compared to high-speed schlieren images and time-resolved total pressure recording. For the latter, a high-frequency pressure probe is placed at the divider outlet, which is shown to resolve the transient total pressure during the shock passage. Moreover, the separation of the shock waves is investigated and found to grow as the divider duct width ratio increases. The numerical and experimental results allow for a better understanding of the dynamic evolution of the flow inside the divider and inform its capability to reduce the pressure pulsations at the exhaust of the pulse detonation combustor.

show abstract

“…1 It is noted that if a classical (control mass, piston-based) Atkinson cycle were under consideration, and Equation (23) was a piston work efficiency rather than a nozzle expansion efficiency, the use of a single T 9 , along with P t4_peak and T t4_peak would be perfectly appropriate since all the mass in this case would follow the same path. Here, Equation (7) has also been employed to produce the final result, which is Equation (6).…”

Section: Performance With Lossesmentioning

confidence: 99%

“…In presenting Equations (2) to (6), no assumptions were made about the uniformity or velocity of the fluid within the control volume. For the remainder of this paper, discussion will return to the originally stated simplifying assumptions that the fluid is uniform and at very low (often zero) velocity.…”

Section: Constant Volume Combustionmentioning

confidence: 99%