Rocket

About: Rocket is a research topic. Over the lifetime, 14018 publications have been published within this topic receiving 95852 citations. The topic is also known as: rockets.

Experimental and Computational Study of Infrared Emission from Underexpanded Rocket Exhaust Plumes

Abstract: Underexpanded rocket exhaust plumes generated in a test-bed facility are studied experimentally. Infrared (IR) images of the plume have been obtained with an IR camera equipped with narrow bandpass e lters. The spectral distribution of the IR emission has been measured with a spectroradiometer. Numerical simulations of the exhaust plume have been conducted. The gas-dynamic and thermodynamic properties of the e owe eld were computed by the General Aerodynamic Simulation Program computational e uid-dynamic code. On the basis of thesimulatede owe eld, theIRradiationwasnumerically calculated byusing a computerprogram INFRAD,which has been developed for this purpose. The program calculates the radiation transfer through the plume using the statistical narrowband model technique. It allows simulation of the IR plume images as well as the local and the space-integrated plume spectra. The simulated and experimental results agree well.

An Approach to Improved Credibility of CFD Simulations for Rocket Injector Design

Abstract: Computational fluid dynamics (CFD) has the potential to improve the historical rocket injector design process by simulating the sensitivity of performance and injector-driven thermal environments to. the details of the injector geometry and key operational parameters. Methodical verification and validation efforts on a range of coaxial injector elements have shown the current production CFD capability must be improved in order to quantitatively impact the injector design process.. This paper documents the status of an effort to understand and compare the predictive capabilities and resource requirements of a range of CFD methodologies on a set of model problem injectors. Preliminary results from a steady Reynolds-Average Navier-Stokes (RANS), an unsteady Reynolds-Average Navier Stokes (URANS) and three different Large Eddy Simulation (LES) techniques used to model a single element coaxial injector using gaseous oxygen and gaseous hydrogen propellants are presented. Initial observations are made comparing instantaneous results, corresponding time-averaged and steady-state solutions in the near -injector flow field. Significant differences in the flow fields exist, as expected, and are discussed. An important preliminary result is the identification of a fundamental mixing mechanism, accounted for by URANS and LES, but missing in the steady BANS methodology. Since propellant mixing is the core injector function, this mixing process may prove to have a profound effect on the ability to more correctly simulate injector performance and resulting thermal environments. Issues important to unifying the basis for future comparison such as solution initialization, required run time and grid resolution are addressed.

Electron time dispersion

Abstract: Observations of electrons during a sounding rocket flight from Sondrestromfjord, Greenland, in 1985 showed numerous instances of electron time-of-flight dispersion, that is, a coherent structure in which fast electrons arrived before slow electrons. The instrumentation measured many pitch angles simultaneously with high time resolution, providing a detailed view of the temporal evolution of the electron signature at rocket altitudes which was indicative of an impulsive injection of electrons over a range of energies. A model utilizing an extended, quasi-static (static on a timescale of 1 s), parallel electric field was developed to investigate a possible mechanism for the injection of these electrons. The model is found to fit the data well only when a background is added which cannot be self-consistently generated by the model, although other parameters used in the model are in general agreement with previous reports. This leads to the conclusion that electron dispersion is more probably generated by a wave acceleration mechanism.

Strutjet Engine Performance

Abstract: To increase the technology readiness level of hypersonic scramjet technology, an innovative strut-based dualmoderamjetenginedesign capableofpoweringa hypersonicvehicleatspeedsfrom Mach4to 8isinvestigated.Two versions of the engine are under development: a dual-mode (ramjet/scramjet )engine formissile applicationsand a rocket-based combined cycle engine for space access. This paper will discuss the features of the dual-mode engine design and how they contribute to overall engine performance. Engine component performance was evaluated using a combination of analysis and component testing. Inlet performance data (mass capture, pressure recovery, and inlet/isolator pressure ratio ) were obtained from wind-tunnel testing and correlated with model and full-scale computational e uid dynamics (CFD)analyses. Combustorperformance data (combustion efe ciency, fuel-injection performance, and pressure distributions ) were obtained from full-scale direct-connect combustor testing. Nozzle losses and efe ciency were obtained from CFD analysis. Performance parameters derived from these component tests and analyses were fed into a standard hypersonic engine cycle code to predict e ight engine performance. The demonstrated component performance values were extrapolated to determine predicted component performance at the end of engine development, which were used to compute the vision e ight engine performance.