Topic
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.
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08 Jul 1985TL;DR: In this paper, the authors made a detailed analysis of the three-dimensional mixing, chemical reaction, and flow field development in a typical ducted rocket configuration and numerically solved the partial differential equations by an iterative finite-difference solution procedure.
Abstract: Calculations have been made of the three-dimensional mixing, chemical reaction, and flow field development in a typical ducted rocket configuration The governing partial differential equations are numerically solved by an iterative finite-difference solution procedure The physical models include the k approx epsilon turbulence model, one-step reaction, and mixing controlled chemical reaction rate Radiation is neglected The mean flow structure, fuel dispersal patterns, and temperature field are presented in detail for a base configuration with 0058 m (2 in) dome height, 45/sup 0/ side arm inclination, and with gaseous ethylene injected from the dome plate at an eccentric location In addition, the influences of the geometrical parameters such as dome height, inclination of the side arms, and location of the fuel injector are studied
28 citations
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TL;DR: In this article, a single-port circular-section polyethylene grain is considered, and the oxidizer is 85% hydrogen peroxide; the engine design is optimized to search for the minimum engine mass when the initial satellite mass and the required velocity increment are assigned.
Abstract: The parameters that affect the design of a hybrid rocket for small satellites are highlighted, and the benefit of the oxidizer flow rate control is analyzed. A single-port circular-section polyethylene grain is considered; the oxidizer is 85% hydrogen peroxide. The engine design is optimized to search for the minimum engine mass when the initial satellite mass and the required velocity increment are assigned. First, the simplest blowdown feed system is considered. The analysis shows that the optimal design depends on a lower limit for the regression rate and sometimes on a further constraint, which is related to the occurrence of thermal choking. The initial values of the mixture ratio, the thrust level and the initial port area to the throat area ratio seem to be the most important parameters for an optimal design. As far as the oxidizer flow rate control is concerned, several control strategies, namely, constant mixture ratio, repressurization, constant combustion chamber pressure, and constant propellant tank pressure, are compared to the simplest blowdown system. The constant mixture ratio control is the worst case, as the mass and volume are similar to the blowdown case, while a large thrust variation occurs. Repressurization reduces the thrust variation. Constant pressure controls (both combustion chamber and tank pressures) guarantee a quasi-constant thrust and reduce engine dimensions, with a limited mass penalty.
28 citations
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24 Jul 2000TL;DR: The experimental results from the study of the rocket-ejector mode of a rocket-based combined cycle (RBCC) engine are presented and discussed in this paper, where the experiments involved systematic flowfield measurements in a two-dimensional variable geometry rocket ejector system.
Abstract: The experimental results from the study of the rocket-ejector mode of a Rocket Based Combined Cycle (RBCC) engine are presented and discussed. The experiments involved systematic flowfield measurements in a two-dimensional variable geometry rocket-ejector system. The rocket-ejector system utilizes a single two-dimensional gaseous oxygen/gaseous hydrogen rocket as the ejector. To gain a thorough understanding of the rocket-ejector's internal fluid mechanic/combustion phenomena, experiments were conducted with both direct-connect and sea-level static configurations for a range of rocket operating conditions. Overall system performance was obtained through global measurements of wall static pressure profiles, heat flux profiles and engine thrust, whereas detailed mixing and combustion information was obtained through Raman spectroscopy measurements of major species (oxygen, hydrogen, nitrogen and water vapor). Rocket-ejector experimental results for both the Diffusion and Afterburning (DAB) and Simultaneous Mixing and Combustion (SMC) geometries are presented here. For the DAB configuration, experiments were conducted for both direct-connect and sea-level static configurations, whereas SMC
28 citations
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TL;DR: In this paper, a ready-made central strut-based rocket-based combined-cycle (RBCC) engine was numerically investigated in the ejector mode, and the flow features and operation characteristics in the RBCC inlet were strongly correlated with the flight conditions, inlet configuration, and operation of the embedded rocket.
28 citations
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TL;DR: In this article, the authors used acoustic streaming theory modified by heat addition and radial flow effects to predict tangential velocity at the periphery of a solid propellant rocket, typically a few hundred feet per second.
Abstract: Vortices are generated by acoustic oscillations as a second-order viscous effect. Traveling tangential modes in an axially perforated solid propellant rocket give a single vortex swirling about the axis. Tangential velocity at the periphery, typically a few hundred feet per second, can be predicted approximately using acoustic streaming theory modified by heat addition and radial flow effects. Serious consequences of the vortex are 1) torque, which gives undesired roll, especially in large vehicles as torque varies as (radius), and 2) pressure rise caused largely by reduction in the effective area of the nozzle throat. Standing tangential modes produce a pair of vortices rotating in opposite directions for each pressure antinode. These give no net torque and are much less destructive. Experimental data include 3200 frames/ sec cine-films of the vortices, torque measurements, and radial pressure gradient determinations in the head end of a motor. The traveling tangential modes can be initiated readily by tangential injection of nitrogen into the motor.
28 citations