Browse Topic: Scramjet engines

Items (21)
Find
How Jet Engine Flow Can Be Controlled OpticallyTBMG-523281/1/2025
What if the future of space travel were to look less like Space-X’s rocket-based Starship and more like NASA’s “Hyper-X,” the hypersonic jet plane that, 20 years ago this year, flew faster than any other aircraft before or since?
On the Aero-Thermo-Structural Performance of Rectangular and Axisymmetric Scramjet Configurations2024-26-04416/1/2024
Scramjet-based hypersonic airbreathers are needed for next-generation defense and space applications. Two scramjet configurations, namely, rectangular and axisymmetric, are primarily studied in the literature. However, there is no quantitative comparison of the performance metrics between these two scramjet configurations. This study investigates the aero-thermo-structural performance of rectangular and axisymmetric scramjet engines at Mach 7 and 25 km altitude. A numerical framework involving computational fluid dynamics and computational structural dynamics is established. The aero-thermo-structural loads on the scramjet flow path are estimated using RANS/FANS simulation. A finite element-based coupled thermo-structural analysis is performed to understand the thermo-structural response. Before using the numerical models for the study, CFD and CSD modules are validated with literature data. The presence of oblique shocks in rectangular scramjets provides better compression than
Nagarajan Kirupakaran, Gopinath, K V, Govindarajan, Roy Mahapatra, Debiprosad
Thermal Analysis of Prismatic Core Sandwich Structural Panel for Hypersonic Application2024-26-04226/1/2024
Hypersonic flight vehicles have potential applications in strategic defence, space missions, and future civilian high-speed transportation systems. However, structural integration has significant challenges due to extreme aero-thermo-mechanical coupled effects. Scramjet-powered air-breathing hypersonic vehicles experience extreme heat loads induced by combustion, shock waves and viscous heat dissipation. An active cooling thermal protection system for scramjet applications has the highest potential for thermal load management, especially for long-duration flights, considering the weight penalty associated with the heavier passive thermal insulation structures. We consider the case of active cooling of scramjet engine structural walls with endothermic hydrocarbon fuel. We have developed a semi-analytical quasi-2D heat transfer model considering a prismatic core single cooling channel segment as a representative volume element (RVE) to analyse larger-scale problems. The model includes
Mukherjee, Ragini, Roy Mahapatra, Debiprosad
Pushing the Limits: Engineering Advanced RF Interconnects to Meet the Challenges of Hypersonic Missile Development24AERP05_055/1/2024
The development of hypersonic missiles represents the most significant advancement of defense weaponry since the 1960s. However, they also pose unique challenges for both design and technology. The term “hypersonic” refers to any speed faster than five times the speed of sound, or above Mach 5. Modern hypersonic missile systems require extensive communications interconnects within a highly confined space. This space requirement creates a demand for solutions combining small form factor with reduced weight and rugged construction to withstand high vibration and impact conditions from deployment to target. Currently there are two types of hypersonic weapons. Hypersonic glide vehicles (HGVs), also known as boost-glide vehicles, typically launch from ballistic missiles and are released at a specific altitude, speed, and with the flight path tailored to a target without being powered. Hypersonic cruise missiles (HCMs) are powered all the way to their targets, flying at lower altitudes than
Comparative Analysis and Testing the Performance of Various Fuels in Ramjet2023-01-51772/23/2024
The development of ramjet engines has experienced a significant increase in response to the growing demand for supersonic speed capabilities in contemporary propulsion systems and missile weaponry. Their efficient operation at supersonic speeds has garnered increased attention. The study focuses on designing a diffuser and ram cone for decelerating supersonic flow in the combustion chamber. Performance tests for hydrogen and ethanol fuels are conducted at Mach values of 3.5, 3, and 2.5. Injectors are positioned asymmetrically in parallel, perpendicular, and at a 45-degree angle to the flow. Effects of injector orifice diameters (0.8mm, 1mm, 1.2mm) on atomization and penetration length distribution are investigated. SolidWorks is used for design, and Ansys with a coupled implicit second-order upwind solver analyzes the Reynolds-averaged Navier-Stokes equation. Eddy dissipation handles combustion. Hydrogen and ethanol are modeled and injected, reacting with atmospheric oxygen. Integral
Chinta, Yuvaraj, Gajula, Phanindra Rao, Basireddy, Charan Venkata Sai Reddy, G, Dinesh Kumar, V, Paulson
Using Numerical Simulation to Obtain Length of Constant Area Section in Scramjet Combustor01-13-01-00043/16/2020
Constant area section length downstream to the fuel injection point is a crucial dimension of scramjet duct geometry. It has a major contribution in creating the maximum effective pressure inside the combustor that is required for propulsion. The length is limited by the thermal choking phenomenon, which occurs when heat is added in a flow through constant area duct. As per theory, to avoid thermal choking the constant area section length depends upon the inlet conditions and the rate of heat addition. The complexity related to mixing and combustion process inside the supersonic stream makes it difficult to predict the rate of heat addition and in turn the length. Recent efforts of simulating the reacting flow inside scramjet combustors are encouraging and can be useful in this regard. The presented work attempts to use simulation results of scramjet combustion for predicting the constant area section length for a typical scramjet combustor. Though the technique appears to be simple
Barpande, Girish, Singh, Amarjit, Pavithran, S.
Beam Shaping for CARS Measurements in Turbulent EnvironmentsTBMG-2350012/1/2015
Taking measurements in a scramjet engine is particularly challenging because of the harsh testing environment. Any probe inserted in the flow would generate shock waves, strongly perturbing the flow. Coherent Anti-Stokes Raman spectroscopy (CARS) is a non-intrusive laser-based measurement technique that has been implemented successfully to measure temperature and species concentrations in ducted scramjet engines.
Dual-Cavity Rayleigh Scattering Measurement SystemTBMG-218084/1/2015
Molecular-based optical diagnostics techniques capable of obtaining simultaneous measurements of multiple fluid properties are critically important for characterizing hypersonic air-breathing engines, such as scramjet engines and scramjet-rocket combined cycle engines. Correlations between those properties lead to a more detailed understanding of complex flow behavior, and aid in the development of multiparameter turbulence models required for supersonic combustion engine flow path predictions.
Multi-Component, Multi-Point Interferometric Rayleigh/Mie Doppler VelocimeterTBMG-127812/1/2012
An interferometric Rayleigh scattering system was developed to enable the measurement of multiple, orthogonal velocity components at several points within very-high-speed or high-temperature flows. The velocity of a gaseous flow can be optically measured by sending laser light into the gas flow, and then measuring the scattered light signal that is returned from matter within the flow. Scattering can arise from either gas molecules within the flow itself, known as Rayleigh scattering, or from particles within the flow, known as Mie scattering. Measuring Mie scattering is the basis of all commercial laser Doppler and particle imaging velocimetry systems, but particle seeding is problematic when measuring high-speed and high-temperature flows.
Diode Laser Sensor for Scramjet InletsTBMG-885112/1/2010
The supersonic combustion ramjet (scramjet) engine is one of the more promising high-speed flight propulsion technologies. One of the reasons for this is the simplicity of the engine design, having no moving parts and requiring no external ignition source, and the fact that scramjets do not need to provide their own oxidizer. Despite this simplicity, several obstacles to the use of scramjet propulsion systems have become apparent, including the ability to produce sufficient fuel-air mixing at high speed, large total pressure losses, reduction in specific impulse with increasing flight Mach number, and the sensitivity of combustion to inlet temperature. This last problem can be very significant.
The Future of Space PropulsionTBMG-489410/1/2008
Significant challenges and advances in space propulsion have occurred over the past ten years. The end of the Cold War had significant impacts, both positive and negative. Operational systems now have to operate well beyond their design life. Parts and technology obsolescence are having a significant impact, as are an aging workforce and limited opportunities to develop new systems. The advent of asymmetric warfare is fully upon us. The military has to pro - ject power anywhere on the globe. In addition, there is concern that U.S. space assets are vulnerable in this new world. Furthermore, changes in acquisition policy driven by incredible cost and schedule overruns on nearly every space acquisition program will have significant impacts on the future of propulsion.
Measuring Skin Friction in Complex Flows That Include ShocksTBMG-475412/1/2007
A methodology for measuring skin friction (also known as wall shear) in complex flows typical of those inside supersonic-combustion ramjet (scramjet) engines has been developed. The flows inside scramjet engines are turbulent and include shocks. Because the dynamic pressures of such flows are high, even small skin-friction coefficients can significantly degrade engine performance. Hence, it is desirable to measure skin friction in order to gain better understanding of engine performance and to enable calibration of skin-friction submodels of computational fluid dynamics models used to design scramjet engines. The presence of shocks and the large heat fluxes associated with flows in scramjet engines add to the challenge of measuring skin friction, and the present methodology provides means to meet the challenge. Major elements of the methodology are a generic design for a gauge and techniques for processing the readings of the gauge such that the wall shear at the gauge location can be
System for Imaging Turbulent Combustion FlowsTBMG-471110/1/2007
Asystem of scientific instrumentation and data-processing equipment has been assembled for research and education in turbulence, mixing, and chemical reactions (especially combustion) in high-speed laminar and turbulent flows. The system is designed to enable study of temporally varying, three- dimensional structures in flow regimes that have been inaccessible to prior instrumentation systems, with emphasis on flow regimes relevant to the operation of ramjet and scramjet engines.
Real-Time Simulation of Aeroheating the Hyper-X AirplaneTBMG-1681/1/2005
A capability for real-time computational simulation of aeroheating has been developed in support of the Hyper-X program, which is directed toward demonstrating the feasibility of operating an air-breathing ramjet/scramjet engine at mach 5, mach 7, and mach 10. The simulation software will serve as a valuable design tool for initial trajectory studies in which aerodynamic heating is expected to exert a major influence in the design of the Hyper-X airplane; this tool will aid in the selection of materials, sizing of structural skin thicknesses, and selection of components of a thermal-protection system (TPS) for structures that must be insulated against aeroheating.
A good defenseAEROMAR04_023/1/2004
Current military propulsion programs range from the tried and true that no one thought possible 50 years ago, to those that some might not think possible 50 years from now. It's been just over 100 years since the first flight of a powered aircraft, and it is also probably just a little over 100 years since someone on the ground had the idea to use the newly proven technology for military purposes. Today, while the skill of the person inside the plane has much to do with winning-and, possibly, avoiding-a battle, lives depend on the reliability of propulsion systems, which are not our grandfathers' propulsion systems. One example of this involves researchers from NASA's Marshall Space Flight Center and Dryden Flight Research Center and the University of Alabama. Late last year the team developed and demonstrated an aircraft that can fly via propulsive power delivered solely by a ground-based laser. The laser tracks the aircraft in flight and directs its beam at specially designed
Broge, Jean L.
Mach Flow Angularity Probes for Scramjet Engine Flow Path Diagnostics9325519/1/1993
Mach-flow angularity probes were developed for use in scramjet flow path probe rakes. Prototype probes were fabricated to demonstrate the assembly processes (numerical control machining, furnace brazing, and electron beam welding). Tests of prototype probes confirmed the thermal durability margins and life cycle. Selected probes were calibrated in air at Mach numbers from 1.75 to 6.0. Acceptance criteria for the production probes stressed thermal durability and pressure (and, consequently, Mach number) measurement quality. This new water-cooled MFA probe has 0.397-cm shaft diameter and is capable of withstanding heat fluxes of 2.724 kW/cm2.
Jalbert, Paul A., Hiers, Robert S.
NUMERICAL SIMULATION OF FLOW THROUGH THE LANGLEY PARAMETRIC SCRAMJET ENGINE8923149/1/1989
The numerical simulation of a three-dimensional turbulent, reacting flow through the entire Langley parametric scramjet engine has been obtained using a piecewise elliptic approach. The last section in the combustor has been analyzed using a parabolized Navier-Stokes code. The facility nozzle flow was analyzed as a first step. The outflow conditions from the nozzle were chosen as the inflow conditions of the scramjet inlet. The nozzle and the inlet simulation were accomplished by solving the three-dimensional Navier-Stokes equations with a perfect gas assumption. The inlet solution downstream of the scramjet throat was used to provide inflow conditions for the combustor region. The first two regions of the combustor were analyzed using the MacCormack's explicit scheme. However, the source terms in the species equations were solved implicitly. The finite rate chemistry was modeled using the two-step reaction model of Rogers and Chinitz. A complete reaction model was used in the PNS code
Srinivasant, Shivakumar, McClinton, Charles R., Kamath, Pradeep S.
Advanced Airbreathing Propulsion Cycles For High Speed Flight8812028/1/1988
Sustained high speed flight cannot be achieved by improvements in traditional turbojet/turbofan propulsion systems. Instead, propulsion cycles optimized for high speed flight are required. These include combined cycles such as the air turboramjet for the lower speed regime, and scramjet-type cycles for the higher speed regime. Characteristics of these advanced airbreathing propulsion cycles are discussed, and propulsion-related technology issues are addressed.
Campbell, J.V., Kissinger, R.D., Kors, D.L.
Environmental Effects on Rotor Tipjet PropulsionSM_WF_1956-261410/1/1956
From Summary: The ramjet, propelled YHJ-1 Hiller Helicopter and 8RJ22 ramjets were u ed as test equipment for a general study of the problem of rotor tip-mounted jet, engines. Air flow through the helicopter rotor, and particularly in the neighborhood of the tipjet engines, has been visualized by using smoke filaments. Notion pictures were taken at speeds ranging from 64 to 1000 pictures per second, both on the whirlstand and the YHJ-1 helicopter. The pictures reveal details of the flow in the region of'he tipjet engine, as well as overall flow through the helicopter rotor in flight.
Sargent, E.R., Lockwood, R.M., Gates, M.F.
Special Power PlantsSM_WF_1955-43129/21/1955
When we were first invited to participate in this panel discussion, it was suggested that since McDonnell has had some experience with pulse jet, ram jet, pressure jet, gas turbine, and reciprocating engines we might comment upon the application of these various propulsion systems to the helicopter.
Ostroff, H.H.
Ramjet Boost for HelicoptersSM_WF_1954-399411/4/1954
From Summary: The problem of supplying additional power to a helicopter rotor for take-off or hovering under overload, hot-day, or altitude conditions is discussed briefly, and the boost system requirements are defined qualitatively. The Marquardt Aircraft Co. is in the process of developing a novel ramjet engine to meet these requirements under the sponsorship of the United States Air Force, The progress to date is reviewed, and the eventual application of this engine is discussed.
Devault, R.T.
Items per page:
1 – 21 of 21