Croker, deputy chief computational sciences branch air vehicles directorate air force research laboratory wrightpatterson afb, oh 45433 barry. Jan 31, 2009 numerical investigations were performed with a supersonic inlet system installed with a threedimensional bump which was substituted for a diverter or conventional ramptype compression systems at mach 2. The design and analysis of supersonic inlets have been under. Subsonic and supersonic air intakes linkedin slideshare. In addition, the nature of supersonic flow makes this inlet more difficult to design and integrate into the airframe. The propulsion systems of jet aircraft are composed of three mayor parts. Pdf the numerical studies are conducted to establish an optimum design of a supersonic intake. Externalcompression supersonic inlet design code a computer code named supin has been developed to perform aerodynamic design and analysis of externalcompression, supersonic inlets. It consists of a bump and a forwardswept inlet cowl, which work together to divert boundary layer airflow away from the aircrafts engine. A well designed subsonic a 1 inlet will produce a stagnation pressure recovery. At a flight mach number of 3 the ideal pressure ratio is. Reducedorder modeling of twodimensional supersonic.
Before the f22, classic supersonic fighters used brute force afterburners and had extremely limited duration. An advanced highspeed inlet for propulsion systems to power air transport vehicles at supersonic speeds has completed testing at nasas glenn research center, cleveland. Supersonic diffuser article about supersonic diffuser by. The inlet achieves better pressure recovery in compressing the air and reducing it to subsonic speeds through the use of multiple oblique shock waves, which are weaker than normal shock waves. This is the most common design for inlets used in supersonic aircraft. Mar 04, 2014 subsonic and supersonic air intakes jet propulsion sanjay singh asst. Supersonic engine inlets for airbreathing engines on supersonic vehicles, usually want to slow flow down to subsonic speeds inside engine need diffuser m1m supersonic inlets computational tools are being developed for the design and analysis of supersonic inlets. The modified inlets were designed to have two oblique shocks and a terminal normal shock followed by a subsonic diffuser, with a circular crosssection throughout. Glenn recently completed testing on an advanced highspeed inlet for propulsion systems to power air transport vehicles at supersonic speeds. For airbreathing engines on supersonic vehicles, usually want to slow flow down to subsonic speeds. However, such approaches usually require a number of ow eld computations proportional to the number of design variables to obtain the gradients. Figure 1 axisymmetric and twodimensional supersonic. Experimental investigation of corner flows in rectangular supersonic inlets with 3d shockboundary layer effects w.
Aerodynamic design of a supersonic threedimensional inlet. Fluidic control of an aggressive offset diffuser for a supersonic inlet. Numerical study on performance of supersonic inlets with. On hammershock propagation in a supersonic flow field. Intakes with an external compression overall contraction ratio. Supersonic inlet article about supersonic inlet by the free. A similar method has been used for the design of threedimensional wings with nacelles4for a supersonic transport. The inlet also has a set of aft bypass doors, controlled by the pilot. Time frequency analysis and detection of supersonic inlet. Driscoll university of michigan, ann arbor, michigan 48109. Supersonic flow over a wedge surface has an attached, straight oblique shock wave from the nose. Vgs can mitigate flow separations within supersonic inlets. Investigation of flow control for the hypersonic inlets via. Reducedorder modeling of twodimensional supersonic flows with applications to scramjet inlets derek j.
Inlets for supersonic missiles aiaa education series. Driscoll2 university of michigan, ann arbor, mi, 48109 john a. Combining equations 6 and 9 gives an expression for the shock mach. The inlet tools effort includes aspects of creating an electronic. The inlet lip is sharpened to minimize the performance losses from shock waves that occur during supersonic flight. A dualstream, lowboom supersonic inlet designed for use on a small, mach 1. An experimental investigation of flow control for supersonic inlets. Highperformance supersonic missile inlet design using. The inlet has an internal pressure sensor, and when it detects that the pressure has grown too great, it triggers the forward bypass doors to open, expelling excess air. The objective is to update existing tools and provide design and loworder aerodynamic analysis capability for advanced inlet concepts. Nasa lewis 8 by 6foot supersonic wind tunnel user manual, nasa tm. Wellperforming supersonic inlets on gas turbine engines must provide uniform, stable, and subsonic flow before the engine face for compression and combustion.
Losses and flow distortions in a supersonicinlet aggressive offset diffuser. Experimental investigation of corner flows in rectangular. To achieve high performance levels, the mixedcompression inlet will need to operate close to its stability limit, much closer than military supersonic inlets. These records are issued from an experimental study that was presented in a previous paper. Jun 07, 2004 an advanced highspeed inlet for propulsion systems to power air transport vehicles at supersonic speeds has completed testing at nasas glenn research center, cleveland. As the slowed, but still supersonic, air continues to move farther into the inlet, the normal shock wave springs up between the inlet throat and the engine compressorexactly where it is supposed to be. On hammershock propagation in a supersonic flow field nasatm2002211717 july 2002. Feb 19, 2014 supersonic inlets the supersonic inlet is required to provide the proper quantity and uniformity of air to the engine over a wider range of flight conditions than the subsonic inlet is. The approach aims to find the optimal inlet geometry which has maximum total pressure. The designer also needs to estimate the total pressure recovery at the engine face in. Results from computational analysis supersonic inlet ntrs nasa.
Compared to typical inlets in this operating range, tests showed high pressure recovery, low cowl drag, reduced complexity, increased safety, significant manufacturing cost reduction and weight, as well as increased efficiency, said david lam. A new methodology has been developed for the design of hypersonic scramjet inlets using gas dynamic relations. The method consists of changing the size of the entering stream tube by means of an inflatable boot on the surface of the central body. On the design of hypersonic inwardturning inlets capt. Design and performance analysis of supersonic inlets using. Supersonic engine inlets georgia institute of technology. The starting of the buzz has been related to the existence in the flow field of a velocity discontinuity across a vortex sheet which originates at a shock intersection. A diverterless supersonic inlet dsi is a type of jet engine air intake used by some modern combat aircraft to control air flow into their engines. Memorandum presenting an investigation of the phenomenon of the starting of aerodynamic instability or buzz in supersonic inlets with external compression. Memorandum presenting a method for varying the mass flow of supersonic inlets with a circular cross section and a central body. At lower supersonic speeds, one type of inlet to use is an internalexternal compression intake, which produces a series of mild shock waves to reduce flow speed to subsonic without.
The flow downstream of the shock is uniform and parallel to the surface with a surface pressure equal to the static pressure behind the shock, p2w. An inlet for a supersonic aircraft, on the other hand, has a relatively sharp lip. Externalcompression inlets have the supersonic diffusion taking place at or ahead of the cowl lip or throat station and generally employ one or more oblique shock waves ahead of the normal shock. The origin of aerodynamic instability of supersonic inlets at. This means airplanes that can cruise supersonically. The results of designing and numerical gasdynamic modeling a supersonic threedimensional inlet of a new type are considered. The shock is a function of the free stream mach number. Combine all the developed modules in association with the. A new approach for the design of hypersonic scramjet inlets. For the best thermodynamic efficiency it is important that this compression be as nearly reversible isentropic as possible. As an example, consider the two defined supersonic missions for the. Analysis of buzz in a supersonic inlet glenn research center. Combining these conditions with the nozzle exit mach number allows the. The supersonic diffuser for supersonic and the subsonic diffuser, it is long and heavy.
The baseline set of inlets include axisymmetric pitot, twodimensional singleduct, axisymmetric outwardturning, and twodimensional bifurcatedduct inlets. Supersonic compression systems can be classified into three basic types. Additional information from the flight manual 25, some nasa reports 2629, and. Inlets for supersonic missiles aiaa education series mahoney, john j. Supersonic inlet buzz and, in particular, its onset were studied through the analysis of pressure records. Internalcompression inlets accomplish supersonic diffusion. A cfd investigation of a generic bump and its application to. Supersonic engine inlets for airbreathing engines on supersonic vehicles, usually want to slow flow down to subsonic speeds inside engine need diffuser m1m engine inlet exception. It is a constant balancing act to keep the normal shock wave in the right position. Neither of these types of inlets do well at higher supersonic speeds, due to shockwaves that form on the lip of the inlet, reducing the efficiency of the inlet. The overall inlet design, called a diverterless supersonic inlet or dsi, moved from concept to reality when it was installed and flown on a block 30 f16 in a highly successful demonstration program.
Chima national aeronautics and space administration glenn research center cleveland, ohio 445 abstract a dualstream, lowboom supersonic inlet designed for use on a small, mach 1. Goals are to maximize total pressure recovery, limit total pressure distortion, and limit inlet drag. The performance of the engine inlet is largely affected by the shockboundary layer interactions sblis. In order to improve the performance of the flow field, counterflow is applied to control the shock reflection configuration in the hypersonic inlets. This requirement highlights the importance of the inlet control system on the inlet design and the ability of the inlet to handle atmospheric disturbances and inlet unstarts. Design of top mounted supersonic inlets for a cylindrical fuselage.
Mixed compression engine inlets are designed to improve the efficiency of supersonic flight vehicles. In the former case, an oblique shock system forms upstream of the cowl leading edge, followed by a terminal normal shock located at the cowl. The flight test program consisted of twelve flights flown in nine days in december 1996. The farther back over the cone the air moves, the more speed it bleeds off. The designer needs to know the size of the inlet in order to properly account for it during the conceptual and preliminary design stage. Supersonic inlet aerodynamics involves flow compression, flow deceleration, shock waves, turbulent boundary layers, shock boundary layer interactions, separated flow, flow control, etc.
Reducedorder modeling of twodimensional supersonic flows. Air force research laboratory, wrightpatterson air force base, oh, 45433 abstract in a rectangular supersonic inlet the first. Driscollz university of michigan, ann arbor, mi, 48109 doi. Control of supersonic mixedcompression inlets using localized arc. Diverterless supersonic inlet dsi the diverterless supersonic inlet dsi is a novel air inlet design principle, used most famously on the lockheed martin f35 lightning ii. At supersonic flight speeds the pressure and temperature rise in the inlet can be quite large. Keywords inwardturning, supersonic, engine intakes, low noise. The supersonic air is decelerated by the inlet through a system of shocks. For a supersonic aircraft, the inlet must slow the flow down to subsonic speeds before the air reaches the compressor.
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