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A mechanical pump for use with the Pioneer-Venus probe mass spectrometer inlet system was obtained, and a limited performance testing program, including ultimate/compression ratio tests and throughput tests at three different pump speeds, was performed. Considerable operating experience with the pump was obtained over approximately 200 hours of running. The test results show general agreement with pump specifications.
Development of facility for experimental evaluation of centrifugal pump operating under periodic fluctuations of inlet pressure and flow
Marshall Space Flight Center has developed and demonstrated two direct read force and moment balances for sensing and resolving the hydrodynamic loads on rotating fluid machinery. These rotating balances consist of a series of stainless steel flexures instrumented with semiconductor type, unidirectional strain gauges arranged into six bridges, then sealed and waterproofed, for use fully submerged in degassed water at rotational speeds up to six thousand revolutions per minute. The balances are used to measure the forces and moments due to the onset and presence of cavitation or other hydrodynamic phenomena on subscale replicas of rocket engine turbomachinery, principally axial pumps (inducers) designed specifically to operate in a cavitating environment. The balances are inserted into the drive assembly with power to and signal from the sensors routed through the drive shaft and out through an air-cooled twenty-channel slip ring. High frequency data - balance forces and moments as well as extensive, flush-mounted pressures around the rotating component periphery - are acquired via a high-speed analog to digital data acquisition system while the test rig conditions are varied continuously. The data acquisition and correction process is described, including the in-situ verifications that are performed to quantify and correct for known system effects such as mechanical imbalance, "added mass," buoyancy, mechanical resonance, and electrical bias. Examples of four types of cavitation oscillations for two typical inducers are described in the laboratory (pressure) and rotating (force) frames: 1) attached, symmetric cavitation, 2) rotating cavitation, 3) attached, asymmetric cavitation, and 4) cavitation surge. Rotating and asymmetric cavitation generate a corresponding unbalanced radial force on the rotating assembly while cavitation surge generates an axial force. Attached, symmetric cavitation induces no measurable force. The frequency of the forces can be determined a priori from the pressure environment while the magnitude of the hydrodynamic force is proportional to the pressure unsteadiness.
Pump CFD code validation tests were accomplished by obtaining nonintrusive flow characteristic data at key locations in generic current liquid rocket engine turbopump configurations. Data were obtained with a laser two-focus (L2F) velocimeter at scaled design flow. Three components were surveyed: a 1970's-designed impeller, a 1990's-designed impeller, and a four-bladed unshrouded inducer. Two-dimensional velocities were measured upstream and downstream of the two impellers. Three-dimensional velocities were measured upstream, downstream, and within the blade row of the unshrouded inducer.
The characteristics of a turbine pump for use with the nuclear engine for rocket vehicles are discussed. It was determined that the pump will be a two stage centrifugal pump with both stages having backswept impellers and an inducer upstream of the first stage impeller. The test program provided demonstration of the ability of the selected design to meet the imposed requirements.
The Centaur LOX boost pump was subjected to both the simulated Titan Centaur proof flight and confidence demonstration vibration test levels. For each test level, both sinusoidal and random vibration tests were conducted along each of the three orthogonal axes of the pump and turbine assembly. In addition to these tests, low frequency longitudinal vibration tests for both levels were conducted. All tests were successfully completed without damage to the boost pump.
Pumped helium tests of 51 centimeter bore niobium tin magnetic coils
Steel alloy pump tested in mercury corrosion loop to establish feasibility of design
Qualification tests on auxiliary pump motor
Noncavitating water flow tests of three loaded axial flow pump rotor blades
Noncavitating water flow tests of three loaded axial flow pump rotor blades
Ceramic stresscoat burst and performance test of shrouded, diffusion welded titanium pump impellers for liquid hydrogen pump applications
This viewgraph presentation provides information on Human Factors Process Failure Modes and Effects Analysis (HF PFMEA). HF PFMEA includes the following 10 steps: Describe mission; Define System; Identify human-machine; List human actions; Identify potential errors; Identify factors that effect error; Determine likelihood of error; Determine potential effects of errors; Evaluate risk; Generate solutions (manage error). The presentation also describes how this analysis was applied to a liquid oxygen pump acceptance test.
A process task analysis effort was undertaken by Dynacs Inc. commencing in June 2002 under contract from NASA YA-D6. Funding was provided through NASA's Ames Research Center (ARC), Code M/HQ, and Industrial Engineering and Safety (IES). The John F. Kennedy Space Center (KSC) Engineering Development Contract (EDC) Task Order was 5SMA768. The scope of the effort was to conduct a Human Factors Process Failure Modes and Effects Analysis (HF PFMEA) of a hazardous activity and provide recommendations to eliminate or reduce the effects of errors caused by human factors. The Liquid Oxygen (LOX) Pump Acceptance Test Procedure (ATP) was selected for this analysis. The HF PFMEA table (see appendix A) provides an analysis of six major categories evaluated for this study. These categories include Personnel Certification, Test Procedure Format, Test Procedure Safety Controls, Test Article Data, Instrumentation, and Voice Communication. For each specific requirement listed in appendix A, the following topics were addressed: Requirement, Potential Human Error, Performance-Shaping Factors, Potential Effects of the Error, Barriers and Controls, Risk Priority Numbers, and Recommended Actions. This report summarizes findings and gives recommendations as determined by the data contained in appendix A. It also includes a discussion of technology barriers and challenges to performing task analyses, as well as lessons learned. The HF PFMEA table in appendix A recommends the use of accepted and required safety criteria in order to reduce the risk of human error. The items with the highest risk priority numbers should receive the greatest amount of consideration. Implementation of the recommendations will result in a safer operation for all personnel.
Tests were conducted on two different types of pumps in order to refine the concept and to finalize design details of a positive displacement internal gear pump and a shroudless centrifugal pump. A concept and a system that could be used with pumps to allow a rapid judgement to be made of the suitability of the pump for futher service is developed. Test results and detailed data analysis are included.
A series of tests were conducted in the space power facility to investigate the failure of the Centaur oxidizer boost pump during the Titan/Centaur proof flight February 11, 1974. The three basic objectives of the tests were: (1) demonstrate if an evaporative freezing type failure mechanism could have prevented the pump from operating, (2) determine if steam from the exhaust of one of the attitude control engine could have entered a pump seal cavity and caused the failure, and (3) obtain data on the heating effects of the exhaust plume from a hydrogen peroxide attitude control engine.
A three-phase helical induction electromagnetic pump, designed for the boiler-feed pump of a potassium Rankine-cycle space power system, was built and tested. The pump was tested over a range of potassium temperatures from 900 to 1400 F, flow rates from 0.75 to 4.85 lb/sec, developed pressures up to 340 psi, net positive suction heads (NPSH) from 1 to 22 psi, and NaK coolant temperatures from 800 to 950 F. The maximum efficiency at the pump design point of 3.25 lb/sec flow rate, 240 psi developed pressure, 1000 F potassium inlet temperature, and 800 F NaK coolant temperature was 16.3 percent. The tests also showed successful operation of the pump at an NPSH as low as 1.5 psi without cavitating.
The primary objective of the Phase Change HX payload on the International Space Station (ISS) is to test and demonstrate the viability and performance of Phase Change Material Heat Exchangers (PCM HX). The system was required to pump a working fluid through a PCM HX to promote the phase change material to freeze and thaw as expected on Orion's Multipurpose Crew Vehicle. Due to limitations on ISS's Internal Thermal Control System, a heat pump was needed on the Phase Change HX payload to help with reducing the working fluid's temperature to below 0degC (32degF). This paper will review the design and development of a TEC based liquid-liquid heat exchanger as a way to vary to fluid temperature for the freeze and thaw phase of the PCM HX. Specifically, the paper will review the design of custom coldplates and sizing for the required heat removal of the HX.