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At least 1,207 records · Page 67

Synthetic fuels for ground transportation with special emphasis on hydrogen

The role of various synthetic fuels, for ground transportation in the United States, was examined for the near term (by 1985) and the longer term applications (1985-2000 and beyond 2000). Feasible options include synthetic oil, methanol, electric propulsion, and hydrogen. It is concluded that (1) the competition during the next 50 years will be for the fuels of all types, rather than among the fuels; (2) extensive domestic oil and gas exploration should be initiated concurrent with the development of several alternate fuels and related ancillaries; and (3) hydrogen, as an automotive fuel, seems to be equivalent to gasoline for optimum fuel to air mixtures. As a pollution free, high energy density fuel, hydrogen deserves consideration as the logical replacement for the hydrocarbons. Several research and development requirements, essential for the implementation of hydrogen economy for ground transportation, were identified. Extensive engineering development and testing activities should be initiated to establish hydrogen as the future automotive fuel, followed by demonstration projects and concerted efforts at public education.

Singh, J. J.↗

Analysis of combustion instability in liquid fuel rocket motors

The development of an analytical technique used in the solution of nonlinear velocity-sensitive combustion instability problems is presented. The Galerkin method was used and proved successful. The pressure wave forms exhibit a strong second harmonic distortion and a variety of behaviors are possible depending on the nature of the combustion process and the parametric values involved. A one dimensional model provides insight into the problem by allowing a comparison of Galerkin solutions with more exact finite difference computations.

Wong, K. W.↗

Analysis of Combustion Instability in Liquid Fuel Rocket Motors

The development of a technique to be used in the solution of nonlinear velocity-sensitive combustion instability problems is described. The orthogonal collocation method was investigated. It found that the results are heavily dependent on the location of the collocation points and characteristics of the equations, so the method was rejected as unreliabile. The Galerkin method, which has proved to be very successful in analysis of the pressure sensitive combustion instability was found to work very well. It was found that the pressure wave forms exhibit a strong second harmonic distortion and a variety of behaviors are possible depending on the nature of the combustion process and the parametric values involved. A one-dimensional model provides further insight into the problem by allowing a comparison of Galerkin solutions with more exact finite-difference computations.

Wong, K. W.↗

Aircraft lightning-induced voltage test technique developments

High voltage safety, fuels safety, simulation, and response/measurement techniques are discussed. Travelling wave transit times, return circuit conductor configurations, LC ladder network generators, and repetitive pulse techniques are also discussed. Differential conductive coaxial cable, analog fiber optic link, repetitive pulse sampled data instrumentation system, flash A/D optic link system, and an FM telemetry system are considered.

Crouch, K. E.↗

The use of force feedback control for robotic mating of umbilical fuel lines

Control problems in developing force feedback control to use in remotely connecting, disconnecting, and reconnecting the umbilical fuel lines of the Space Shuttle Vehicle are discussed. A docking protocol is proposed, indicating the required role of force feedback. The use of active force feedback control is examined and performance requirements and experimental results are given. A single degree-of-freedom force feedback model is presented and the application of classical control compensation techniques to the force control loop to increase flexibility is considered. In addition, possible modifications to the controller and plans for future research are discussed.

Fullmer, R.↗

SSME structural dynamic model development

The high pressure fuel turbopump (HPFTP) is a major component of the Space Shuttle Main Engine (SSME) powerhead. The device is a three stage centrifugal pump that is directly driven by a two stage hot gas turbine. The purpose of the pump is to deliver fuel (liquid hydrogen) from the low pressure fuel turbopump (LPFTP) through the main fuel valve (MFV) to the thrust chamber coolant circuits. In doing so, the pump pressurizes the fuel from an inlet pressure of approximately 178 psi to a discharge pressure of over 6000 psi. At full power level (FPL), the pump rotates at a speed of over 37,000 rpm while generating approximately 77,000 horsepower. Obviously, a pump failure at these speeds and power levels could jeopardize the mission. Results are summarized for work in which the solutions obtained from analytical models of the fuel turbopump impellers are compared with the results obtained from dynamic tests.

Foley, Michael J.↗

Developing the test conditions for the first fueled transients in the TREAT reactor

The restart of the Transient Reactor Test (TREAT) facility at Idaho National Laboratory, re-establishes a national in-pile testing capability for nuclear fuels in accident scenarios. The purpose of the first tests in TREAT are to study the response of nuclear fuel durring a reactivity initiated accident (RIA). The initial objective is to demonstrate the ability to create a desired enthalpy increase in a representative fuel test specimen over a desired time step and to better understand the uncertainty. The five test rods initially available for these irradiations are UO2-Zircaloy with standard Pressurized Water Reactor (PWR) geometry. The rods are 15 cm long with 9 cm of active fuel. The initial testing environment is dry helium. BISON fuel performance calculations were run to model the heat transfer during postulated transients. Based on those results energy deposition targets were selected around the range of observable phenomena in the testing environment. Reactor / experiment power coupling factors, step insertion size and transient clipping response times were then calculated using results from a RELAP point kinetics model. Calculated energy deposition targets are 150, 350, 650, 960, and 1300 J/gUO2. The energy coupling factor for the experiments was calculated to be ~1.5 J/gUO2-MJ. Two step insertion sizes were selected: a 0.6% ?k/k step for the 150 J/g transient and a 1.8% ?k/k step for the other transients. Clipping response times ranged from 1.3 seconds to unclipped transients. The experiments will be irradiated in the TREAT facility in the fall of 2018. The first transient will be the 150 J/g pulse with a 0.6% ?k/k step that is unclipped. Follow on tests may modify the reactor operating parameters based on results from previous transients. Any preliminary data available on the results of the transients at the time of the NUMAT Conference will be presented.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗