Shock Tunnel studies on drag reduction of a blunt body using argon plasma jet
08 Jan 2009-
TL;DR: In this paper, an experimental investigation of aerodynamic drag reduction by counter flow plasma jet injection from the stagnation region of a hemispherical blunt cylinder model flying at hypersonic Mach numbers is presented.
Abstract: [] An experimental investigation of aerodynamic drag reduction by counter flow plasma jet injection from the stagnation region of a hemispherical blunt cylinder model flying at hypersonic Mach numbers are presented. Experiments are carried out in a hypersonic shock tunnel at four different jet - to -pitot pressure ratio and differ ent supply powers. The flow fields around the test model are visualized using high speed schlieren technique. Direct force measurement is also performed using a single component accelerometer balance. The weakly ionized argon plasma jet has an electron tem perature around 6400K a nd electron number density ~4.9 X10 15 cm -3 . With plasma jet at pressure ratio 72.5 and 1.8 KW supply power the reduction in drag is found to be ~28% (more than its cold jet counter part) although the plasma jet momentum is less than i ts cold jet counter part.
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TL;DR: The main objective of this analysis is to support a trade-off for the selection of the type of facility to be developed in order to give Europe a ground test with the capabilities to support future exploration and sample return missions.
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TL;DR: In this paper, a series of experiments is described in which a jet issues from an orifice at the nose of a body in supersonic flow to oppose the mainstream, and an analytical model of the flow is developed which suggests that the aerodynamic features of a steady flow depend primarily on a jet flow-force coefficient, and the Mach number of the jet in its exit plane.
Abstract: A series of experiments is described in which a jet issues from an orifice at the nose of a body in supersonic flow to oppose the mainstream. An analytical model of the flow is developed which suggests that the aerodynamic features of a steady flow depend primarily on a jet flow-force coefficient, and the Mach number of the jet in its exit plane. A sufficient condition for steady flow is developed. The experiments are found to agree well with predictions based on the flow model. A short account is presented of some previous investigations, and some of their conclusions are re-examined in the light of the present study.
263 citations
TL;DR: In this paper, a summary of combined experimental and computational investigations is presented for the plasma injection from a hypersonic blunt body for drag reduction, where the experimental investigation was conducted in a nominal Mach 6 open jet, blowdown tunnel and the computational study was carried out by solving both the threedimensional and the axisymmetric, mass-averaged, Navier-Stokes equations for counterflow jet interaction.
Abstract: The summary of combined experimental and computational investigations is presented for the plasma injection from a hypersonic blunt body for drag reduction. The systematic pursuit addresses all speculated mechanisms that can generate favorable magnetoaerodynamic interactions: the counterflow jet shock aerodynamic interaction, the nonequilibrium thermodynamic and chemical phenomenon, and the electromagnetic-aerodynamic interaction. The computational study was carried out by solving both the three-dimensional and the axisymmetric, mass-averaged, Navier-Stokes equations for counterflow jet interaction. The experimental investigation of the plasma injection was conducted in a nominal Mach 6 open jet, blowdown tunnel. The weakly ionized, counterflow jet generated by a plasma torch has a vibrational temperature of 4400 K, an electron temperature around 20,000 K, and electron number density greater than 3 × 10 12 /cm 3
105 citations
TL;DR: In this article, the aerodynamic drag force is measured using the accelerometer based force balance system and the experimental measurements show about 30% −45% reduction in drag coefficient for different jet pressures.
Abstract: Counterflow drag reduction by supersonic jet for a large angle blunt cone at hypersonic Mach number is investigated in a shock tunnel. The flowfields around the test model in the hypersonic flow with an opposing supersonic jet emanating from the stagnation point of the model are visualized by high speed schlieren technique. The aerodynamic drag force is measured using the accelerometer based force balance system. The experimental measurements show about 30%–45% reduction in drag coefficient for different jet pressures.
91 citations
TL;DR: In this article, the effect of plasma and hot-gas injection from a model's surface toward the external environment on aerodynamic dragofthemodel is investigated, and the amount of drag reduction depends on jet stagnation temperature.
Abstract: The ine uence of plasma and hot-gas injection from a model’ s surface toward the external e ow on aerodynamic dragofthemodelisresearched.ExperimentaltestsareconductedintransonicandsupersonicwindtunnelsatMach numbersM1 =0.59‐4. Numerical experiments are carried out using unsteady Euler equations of an ideal perfect gasinintegralconservativeform.ThecalculationswereperformedattheoncomingMachnumber M1 = 4,constant jet stagnation pressure, and jet stagnation temperatures of 600, 2000, and 6000 K. The investigations showed that the plasma or hot-gas injection can be used to reduce drag at subsonic, transonic, and supersonic Mach numbers, resulting in twice (or more)drag reduction. The calculations are in general agreement with the experimental data. The amount of drag reduction depends on jet stagnation temperature.
72 citations
TL;DR: A miniature three-component accelerometer balance system for measuring the fundamental aerodynamic force coefficients over blunt bodies has been designed, fabricated and tested in the Indian Institute of Science hypersonic shock tunnel HST2 at a nominal Mach number of 5.75 as mentioned in this paper.
Abstract: A miniature three-component accelerometer balance system for measuring the fundamental aerodynamic force coefficients over blunt bodies has been designed, fabricated and tested in the Indian Institute of Science hypersonic shock tunnel HST2 at a nominal Mach number of 5.75. The model and the balance system are supported by rubber bushes, thereby ensuring unrestrained free-floating conditions of the model in the test section during the flow duration. Exhaustive axisymmetric finite-element simulations are carried out to select appropriate rubber bushes and materials for the model and the balance system. The internally mountable accelerometer balance is used to measure the drag, lift and pitching moment coefficients for a $60^o$ apex angle blunt cone within the effective tunnel test time of $800\hspace{2mm}{\mu}s$. The measured aerodynamic force coefficients match very well with the theoretical values predicted using modified Newtonian theory at moderate specific enthalpy levels of the test gas.
67 citations