Aerodynamic Design and Analysis of High Performance Nozzles for Mach 4 Accelerator Vehicles

Georgiadis, Nicholas J.; DalBello, T.; Trefny, Charles J.; Johns, A. L.

doi:10.2514/6.2006-16

Cited by 9 publications

(4 citation statements)

References 8 publications

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“…However, the overall length of the nozzle could not exceed 26 in. (5) CRITICAL PRESSURE (P*) (6) Critical flow through a convergent-divergent nozzle is a phenomenon that occurs when the mass flow rate of a gas cannot be increased when the pressure drop across the nozzle is further increased. The ratio between the downstream and upstream pressures at which this occurs is called the critical pressure ratio.…”

Section: Variable Geometry Convergent-divergent Nozzlementioning

confidence: 99%

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Simulation of Back Pressure Effect on Behaviour of Convergent Divergent Nozzle

Mahmood

2013

DJES

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In this research a simulation of steady flow of a gas through a convergent divergent nozzle which has a varying cross sectional area will be considered. The nature of the flow can be explained by considering how the flow and its characteristics in the nozzle changes as nthe back pressure Pb is decreased.The characteristics of gas flow i.e.(Mach number, static pressure, density, velocity magnitude and static temperature) distributions for the convergent divergent nozzle are implemented by using the ANSYS Fluent 12.1 software to solve the quasi-one dimensional nozzle flow.The reductions in the back pressure cannot affect conditions upstream of the throat. The nozzle is, therefore, choked. The shock wave increases the pressure, density and temperature and reduces the velocity and Mach number to a subsonic value, and as back pressure is further reduced to a certain value, the extent of the supersonic flow region increases, the shock wave moving further down the divergent portion of the nozzle towards the exit plane.

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Section: Variable Geometry Convergent-divergent Nozzlementioning

confidence: 99%

“…This region of supersonic acceleration is terminated by a normal shock wave. (5) The shock can occur only in steady state when there is a supersonic flow. the gas has to pass through a converging-diverging nozzle to obtain a supersonic flow.…”

Section: Flow Behaviour In a Convergent-divergent Nozzlementioning

confidence: 99%

Simulation of Back Pressure Effect on Behaviour of Convergent Divergent Nozzle

Mahmood

2013

DJES

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“…To incorporate compressibility effects in turbulence models, and consequently to better predict the decrease in the growth rate with increasing Mach number, an additional compressibility term should be included in the turbulence transport equations (Sarkar 1991;Sarkar et al 1991). and Georgiadis (2006) assessed the accuracy of modified two-equation turbulence models in flow field predictions of a subsonic (Mach number 0.5) heated and unheated jet. They showed that all the modified equations provided improved predictions compared to the standard models.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of an over-expanded supersonic and subsonic industrial nozzle flow relevant to flaring system

Qurooni

Vakil

Elsaadawy

et al. 2019

Transactions of the Canadian Society for Mechanical Engineering

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Flaring in oil and gas production is the controlled burning of unwanted exhaust gases to enhance safety. To improve flare combustion, gas flares are equipped with air nozzles that introduce extra oxygen and improve mixing in the combustion zone. These nozzles are operated in the subsonic, sonic, or supersonic regimes. In this paper, we are concerned with turbulence modeling of the jet flow exiting from a particular convergent–divergent nozzle used in flare systems. That nozzle has convergent and divergent sections that are connected via a throat section with a finite length and constant diameter. The Realizable k – ε and SST k – ω models are used to study the compressible flow within the nozzle. The velocity profiles, turbulent kinetic energy, Mach number profiles, and entrainment rate coefficients predicted by both turbulence models are compared for nozzle pressure ratios in the range 1.18 ≤ NPR ≤ 1.78. It is shown that both turbulence models predict nearly identical flow evolution along the nozzle. When the flow becomes supersonic, the shock surface, and consequently nozzle outlet velocity profiles, predicted by the SST k – ω model deviates slightly from the other model. The differences, however, become negligible a couple of diameters downstream of the nozzle outlet.

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“…To incorporate compressibility effects in turbulence models, and consequently to better predict the decrease in the growth rate with increasing Mach number, an additional compressibility term should be included in the turbulence transport equations [10,11]. Georgiadis et al [12,13] assessed the accuracy of modified two-equation turbulence models in flow field predictions of a subsonic (Mach number 0.5) heated and unheated jet. They showed that all the modified equations provided improved predictions compared to the standard models.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation Of An Over-Expanded Supersonic Nozzle Flow

Qurooni¹,

Vakil²,

Elsaadawy³

et al. 2018

Progress in Canadian Mechanical Engineering

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Flaring in oil and gas production is the controlled burning of unwanted exhaust gases to enhance safety. Obtaining complete combustion and thus eliminating or reducing smoke is critical to meet increasingly strict environmental regulations. To improve flare combustion, gas flares are equipped with air nozzles that introduce extra oxygen and improve mixing in the combustion zone. These nozzles are operated in the subsonic, sonic, or supersonic regimes. In this paper we are concerned with turbulence modeling of the jet flow exiting from a particular convergent-divergent nozzle used in flare systems. The Realizable − and SST − models are used to study the compressible flow within that specific nozzle, which has an exit diameter of 3.38 mm and has convergent and divergent sections that are connected via a throat section with a finite length and constant diameter. The velocity profiles and turbulent kinetic energy predicted by both turbulence models, in the vicinity of the nozzle outlet and along the symmetry axis of the nozzle, are compared for nozzle pressure ratios in the range 1.18 ≤ NPR ≤ 1.78 . It is shown that for ≤ 1, both turbulence models predict nearly identical flow evolution along the nozzle. When the flow becomes supersonic, the shock surface, and consequently nozzle outlet velocity profiles, predicted by the SST − model deviates slightly from the other model. The differences, however, become negligible a couple of diameters downstream of the nozzle outlet. Computed entrainment rate coefficients vary slightly when changing the turbulence model, and this difference remains insignificant with increasing downstream distance.

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Aerodynamic Design and Analysis of High Performance Nozzles for Mach 4 Accelerator Vehicles

Cited by 9 publications

References 8 publications

Simulation of Back Pressure Effect on Behaviour of Convergent Divergent Nozzle

Simulation of Back Pressure Effect on Behaviour of Convergent Divergent Nozzle

Numerical simulation of an over-expanded supersonic and subsonic industrial nozzle flow relevant to flaring system

Numerical Simulation Of An Over-Expanded Supersonic Nozzle Flow

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