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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Open-ended microwave cavity directly measures the density of flowing liquid, gaseous, or two-phase hydrogen. Its operation is based on derived relations between the cavity resonant frequency and the dielectric constant and density of hydrogen.
The paper contains new numerical simulation and experimental test results of blunt body drag reduction using thin spikes mounted in front of a body and one- or two-phase jets injected against a supersonic flow. Numerical simulations utilizing the NASA CFL3D code were conducted at the Hampton University Fluid Mechanics and Acoustics Laboratory (FM&AL) and experimental tests were conducted using the facilities of the IM/MSU Aeromechanics and Gas Dynamics Laboratory. Previous results were presented at the 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference. Those results were based on some experimental and numerical simulation tests for supersonic flow around spike-nosed or shell-nosed bodies, and numerical simulations were conducted only for a single spike-nosed or shell-nosed body at zero attack angle, alpha=0. In this paper, experimental test results of gas, liquid and solid particle jet injection against a supersonic flow are presented. In addition, numerical simulation results for supersonic flow around a multiple spike-nosed body with non-zero attack angles and with a gas and solid particle forward jet injection are included. Aerodynamic coefficients: drag, C(sub D), lift, C(sub L), and longitudinal momentum, M(sub z), obtained by numerical simulation and experimental tests are compared and show good agreement.
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Two-phase heat transfer and fluid flow data for potassium
Alkali metals boiling and condensing investigations of two-phase heat transfer and fluid flow for potassium
Two-phase heat-transfer and fluid-flow characteristics in nucleate boiling of potassium for use in space power systems
Interphase momentum transfer during propagation of infinitesimal pressure pulse through bubbly flow two phase mixture
Design, performance characteristics and testing of two-phase hydrogen pump inducer for use in future spacecraft systems
An experimental study of the inception of boiling in potassium in forced convection is reported. The boiler consisted of a 0.19-inch inside diameter, niobium-1% zirconium boiler tube approximately six feet long. Heating was accomplished by direct electrical tube wall conduction. Experiments were performed with both all-liquid fill and two-phase fill startup sequences and with a range of flow rates, saturation temperatures, inert gas levels, and fill liquid temperatures. Superheat of the liquid above the equilibrium saturation temperature was observed in all the experiments. Incipient boiling liquid superheat ranged from a few degrees to several hundred. Comparisons of these data with other data and with several analytical treatments are presented.
The density measurement of liquid hydrogen and two-phase mixtures of liquid and gaseous hydrogen is considered. This paper describes a complete prototype system that uses an open-ended microwave cavity for making dynamic density measurements of flowing hydrogen in a transfer line. The theory of operation along with test results for both the single- and two-phase cases are presented and discussed.
Thermal modeling of a cryogenic pump and a hot-gas turbine in a turbopump assembly proposed for the Space Shuttle is described in this paper. A model, developed by identifying the heat-transfer regimes and incorporating their dependencies into a turbopump system model, included heat transfer for two-phase cryogen, hot-gas (200 R) impingement on turbine blades, gas impingement on rotating disks and parallel plate fluid flow. The ?thermal analyzer' program employed to develop this model was the TRW Systems Improved Numerical Differencing Analyzer (SINDA). This program uses finite differencing with lumped parameter representation for each node. Also discussed are model development, simulations of turbopump startup/shutdown operations, and the effects of varying turbopump parameters on the thermal performance.
An analog computer study is made of the low-frequency flow dynamics observed with liquid hydrogen flowing in two different nuclear-rocket cold-flow (unfueled) engine systems. The prediction of the low-frequency response depends largely upon the generation of the proper mass-flow storage in the system. This is achieved by relating, in the model lumping, the average values of fluid enthalpy and a certain thermodynamic fluid property. A two-phase state equation is derived for thermodynamic equilibrium between the gas and liquid phases. Parametric studies are made which demonstrate the effect of the pump characteristics on the flow damping.
Computer program for calculating inviscid one-dimensional equilibrium, frozen and nonequilibrium nozzle expansion of propellant exhaust mixtures
An analytical investigation was made of the problems associated with the long-term storage and control of flow of cryogenic propellants for electrothermal engines. Storage of 35 to 174 pounds of propellant for three years is made difficult by the high ratio of surface area to storage tank volume, and the resulting high rate of heat leak. Vented and non-vented storage, storage as high pressure gas, and the use of refrigeration were considered. Recommended storage methods are: for ethane and ammonia vented storage - by venting propellant stored in excess of mission requirements; for hydrogen and helium - by non-vented storage of cold supercritical vapor; and for methane by storage as a non-vented two-phase mixture. The optimum propellant density in the storage tank and optimum insulation thickness were also determined. Design charts were developed for hydrogen and helium, for estimating the maximum pressure expected in non-vented storage tanks, as function of mission requirements. Separation of the constituent phases of liquid-vapor mixtures is achieved by throttling the two-phase mixture to a lower pressure (and temperature) and vaporizing the liquid in the mixture by heat exchange with the contents of the storage tank. The time limitations for continuous use of this method are discussed. Linde super insulations SI-44 or SI -91 are recommended for insulation. Precooling the insulation to temperatures below the steady state level with cold helium vapor before or during fueling of the storage tank eliminates the flow of heat to the tank contents during countdown and take-off. The masses, sizes, and power requirements of the recommended systems are low. The controls are simple and reliable. From the equations and charts in this report the components of the system for a particular mission can be sized. Recommendations are given for experimental work required for the development and testing of such components.
In dusty air flows occurring in industrial practice in transport by air pressure of friable materials, in the drying, annealing, and so forth, of a pulverized solid mass in suspension, and in other processes, the concentration of solid particles usually has a magnitude of the order of 1 kg per 1 kg of air. At such a concentration, the ratio of the volume of the particles to the volume of the air is small (less than one-thousandth part). However, regardless of this, the presence of a solid admixture manifests itself in the rules for the velocity distribution of the air in a dusty air flow. As a result, the rules of velocity change are different for clean and for dusty air flows. The estimation of the influence of the admixture on the velocity of the motion of the flow presents a definitive interest. One of the attempts to estimate that influence on the axial velocity of a free axially symmetrical jet with admixtures was made by Abramovich. Abramovich assumed beforehand that the fine particles of the admixture in the jet are subject to the motion of the air (that is, that the velocity of the admixture is approximately equal to the local velocity of the air); he then took as the basis of his considerations, in solving the problem, the condition that the amount of motion of the two-phase jet must be constant.
Stationary device produces a homogeneous mixture of two or more one-phase or two-phase fluids. The device contains two concentric flow guides with helical passageways through which the fluids are forced into turbulent flow by the system pressure differential.
Simulation of two phase hydrogen venting to space environment, discussing thrust effect measurements, flow instabilities and instrumentation
Two phase critical flow of saturated and subcooled high pressure liquid nitrogen through convergent- divergent nozzle, comparing with water