Engineering topics

Costello, Frederick A.

Publications and source records attributed to Costello, Frederick A..

6 records

NASA NTRS1990

Low-temperature thermal control for a lunar base

The generic problem of rejecting low- to moderate-temperature heat from space facilities located in a hot thermal sink environment is studied, and the example of a lunar base located near the equator is described. The effective thermal sink temperature is often above or near nominal room temperature. A three heat pump assisted thermal bus concept appears to be the most viable as they are the least sensitive to environmental conditions. Weight estimates are also developed for each of the five thermal control concepts studied: (1) 149kg/kW for a central thermal loop with unitary heat pumps; (2) 133 kg/kW for a conventional bus connected to large, central heat pumps at the radiator; (3) 134 kg/kW for a central, dual loop heat pump concept; (4) 95 kg/kW for the selective field-of-view radiator; and (5) 126 kg/kW for the regolith concept.

Swanson, Theodore D.↗

NASA NTRS1990

Modeling the use of a binary mixture as a control scheme for two-phase thermal systems

Two-phase thermal loops using mechanical pumps, capillary pumps, or a combination of the two have been chosen as the main heat transfer systems for the space station. For these systems to operate optimally, the flow rate in the loop should be controlled in response to the vapor/liquid ratio leaving the evaporator. By substituting a mixture of two non-azeotropic fluids in place of the single fluid normally used in these systems, it may be possible to monitor the temperature of the exiting vapor and determine the vapor/liquid ratio. The flow rate would then be adjusted to maximize the load capability with minimum energy input. A FLUINT model was developed to study the system dynamics of a hybrid capillary pumped loop using this type of control and was found to be stable under all the test conditions.

Benner, S. M.↗

NASA NTRS1990

Lunar radiators with specular reflectors

A unique radiator, suitable for use in relatively hot thermal environments such as the moon, has been devised and analyzed. The radiator uses a parabolic specular reflector to deflect the solar rays and to shield the radiator from the hot lunar soil. It can provide sink temperatures on the order of 147 K and effective emittances approximately equal to the emittance of the surface of the radiator. Similar performance can be obtained on sun-oriented spacecraft that have a limited view of space.

Costello, Frederick A.↗

NASA NTRS1990

Fatigue testing of corrugated and Teflon hoses

Single and two-phase heat transport systems for the thermal control of large space facilities require fluid lines that traverse joints and either rotate or move in some other manner. Flexible hoses are being considered as one means of traversing these joints. To test the resilience of flexible hoses to bending stress, a test assembly was constructed to determine the number of flexing cycles the hoses could withstand before losing their ability to maintain a constant pressure. Corrugated metal hoses and Teflon hoses were tested at different pressures with nitrogen gas. The metal hoses had lives ranging from 30,000 to 100,000 flexing cycles. But, even after 400,000 cycles, the Teflon hoses remained essentially intact, though some leakage in the convoluted Teflon is noted.

Benner, Steve M.↗

NASA NTRS1989

The systems improved numerical fluids analysis code (SINFAC)

A computer program has been developed to model the steady-state performance of single and two-phase heat transport systems. The development effort had the intent of making the program general, relatively easy to implement and easy to integrate into currently available software. The primary use of the program is for, but not limited to, heat transport system for spacecraft. In order to show the program has achieved its intended goals, the program was first applied to a small loop and a quick parametric study done. Next a verification study was done in which the temperature data from a thermal loop flown on the space shuttle was compared to modeler predictions.

Schweickart, Russell B.↗

NASA NTRS1989

SINFAC simulation of a high-power hybrid CPL

The systems improved numerical fluids analysis code (SINFAC) was used to model a high-power hybrid capillary-pumped loop. A comparison was made between the simulation results and actual experimental test data for the mechanical-pump-assist mode of operation. The hybrid capillary-pumped loop consisted of a capillary-pumped loop with a mechanical pump in the liquid return line with a bypass value so that the system could be operated either as a capillary-only loop or a series hybrid loop. Excellent agreement was obtained between numerical and experimental data.

Benner, Steve M.↗