Drag and heat reduction efficiency research on opposing jet in supersonic flows

In this research paper, investigations of counter flow (opposing) jet on the aerodynamic performance, and flight stability characteristics of an airfoil with blunt leading-edge in supersonic regime are performed. Unsteady Reynolds-Averaged Navier-Stokes ( U R A N S ) based solver is used to model the flow field. The effect of angle of attack ( α ), free-stream Mach number ( M ∞ ), and pressure ratio ( P R ) on aerodynamic performance of airfoil with and without jet are compared. The results indicate that the opposing jet reduces drag from 30 % to 70 % , improves the maximum lift-to-drag ratio from 2.5 to 4.0, and increases shock stand-off distance from 15 % to 35 % depending on flow conditions. The effect of opposing jet on longitudinal flight stability characteristics, studied for the first time, indicate improvement in dynamic stability coefficients ( C m q + C m α ˙ ) at low angles of attack. It is concluded that the opposing jet can help mitigate flight disturbances in supersonic regime.

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“…At PR = 4, the Mach disc does not maintain its shape as depicted in Figure 11b. The increment in PR increases the mass flow rate [8].…”

Section: Pressure Ratio Effectsmentioning

confidence: 98%

“…The re-circulation region ahead of the blunt body plays a prominent role in the reduction of drag. The effective shock reduction through opposing jets is also dependent on flow conditions and geometric shapes [7,8].…”

Section: Introductionmentioning

confidence: 99%

Shock Reduction through Opposing Jets—Aerodynamic Performance and Flight Stability Perspectives

et al. 2019

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“…In contrast, it was shown that increasing the specific heat ratio pushes the fore shock further away from the body [141]. Jet temperature has a negative impact of the thermal protection capabilities of the jet as it increasing the peak heat transfer at the reattachment point [145,168,169]. Impact of jet temperature on drag reduction capabilities of opposing jet was a point of debate.…”

Section: Factors Controlling the Counterflow Effectivenessmentioning

confidence: 99%

Forebody shock control devices for drag and aero-heating reduction: A comprehensive survey with a practical perspective

Ahmed

Qin

2020

Progress in Aerospace Sciences

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One key feature that distinguishes the flowfield around vehicles flying in supersonic and hypersonic regimes is the bow shock wave ahead of forebody. The severe drag and aeroheating impacting these vehicles can be significantly reduced if the bow shock wave ahead of the vehicles forebodies is controlled to yield weaker system of oblique shocks. Benefits of forebody shock control include increasing flight ranges, economizing fuel consumption, reducing dead weights, and thermally protecting forebody structure and onboard equipment. Forebody shock control that has been widely studied since the early 1900s is achievable in numerous techniques that vary according to the mechanism of control. While some of these techniques have already been implemented in real systems, other techniques involve serious complications and tough trade-offs. The present paper is intended to serve as the first comprehensive survey on the field of forebody shock control devices. The objectives of the present paper are multifold. The paper categorizes the various forebody shock control devices in a physics-based manner, explains the underlying physics for each device, and surveys the key studies and state-of-the-art knowledge. The paper also addresses the existing gaps in knowledge, highlights the existing systems implementing these devices, and discusses the associated practical implementation issues and design-tradeoffs. 2. Structural devices, the mechanical spikes: 2.1. Principle of operation of mechanical spikes Drag and Aeroheating Reduction Devices Fluidic Devices Opposing jets Structural Devices Mechanical spikes Energetic Devices Energy deposition Basic devices Structural-Fluidic Devices Structural-Energetic Devices Hybrid devices

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“…Imoto et al (2011) showed that opposing jet methods can reduce the heat flux stagnation point by over 80% while other researchers have reviewed numerical simulations that show the excellent heat flux reduction of opposing jet methods (Sun et al, 2019). Other research has shown that cooling efficiency can be influenced by operating conditions and physical dimensions, such as jet properties (Huang et al, 2018;Shen et al, 2018) and injector configurations (Barzegar Gerdroodbary et al, 2015;Li et al, 2017). Other thermal protection techniques such as spike (Zhu et al, 2018) and forwardfacing cavity (Lu and Liu, 2013) have also been considered as approaches to improve the efficiency of thermal protection in opposing jet TPS.…”

Section: Introductionmentioning

confidence: 99%

Influence of angle of attack on a combined opposing jet and platelet transpiration cooling blunt nose in hypersonic vehicle

Shen

Liu

2020

J. Zhejiang Univ. Sci. A

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Flying condition with angle of attack is inevitable in a hypersonic vehicle, and it may influence the thermal protection system (TPS) performance of opposing jet and its combinations. A 3D Navier-Stokes equation and shear stress transfer (SST) k-ω model with compressible correction are employed to simulate the angle of attack characteristics of a blunt body with opposing jet and platelet transpiration TPS. The flowfield and heat flux transfer for angles of attack 0°, 3°, 6° with jet pressure ratio PR=0.1 and 0°, 6°, 12° with PR=0.2 are obtained. Numerical results show that the flowfield is no longer symmetrical with the effect of the angle of attack. The flowfield and heat transfer in windward and leeward performed adversely. The recompression shock wave in windward is strengthened, which increases local temperature and strengthens heat transfer. The opposing jet fails in thermal protection when the angle of attack reaches critical value; however, the critical angle of attack can be promoted by increasing PR. Finally, the transpiration gas can strengthen the cooling efficiency of windward, thereby, increasing the critical angle of attack.

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Drag and heat reduction efficiency research on opposing jet in supersonic flows

Cited by 49 publications

References 25 publications

Shock Reduction through Opposing Jets—Aerodynamic Performance and Flight Stability Perspectives

Shock Reduction through Opposing Jets—Aerodynamic Performance and Flight Stability Perspectives

Forebody shock control devices for drag and aero-heating reduction: A comprehensive survey with a practical perspective

Influence of angle of attack on a combined opposing jet and platelet transpiration cooling blunt nose in hypersonic vehicle

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