Inverted Outflow Ground Testing of Cryogenic Propellant Liquid Acquisition Devices

NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMD's), such as screen channel capillary liquid acquisition devices (LAD's), vanes and sponges have been used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic fluid management (CFM) project. System concept studies have looked at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Modeling validated by normal gravity experiments is examining the behavior of the flow in the LAD channel assemblies (as opposed to only prior testing of screen samples) at the flow rates representative of actual engine service (similar in size to current launch vehicle upper stage engines). Recently testing of rectangular LAD channels has included inverted outflow in liquid oxygen and liquid hydrogen. This paper will report the results of liquid oxygen testing compare and contrast them with the recently published hydrogen results; and identify the sensitivity of these results to flow rate and tank internal pressure

Liquid Methane Conditioning Capabilities Developed at the NASA Glenn Research Center's Small Multi- Purpose Research Facility (SMiRF) for Accelerated Lunar Surface Storage Thermal Testing

Glenn Research Center s Creek Road Cryogenic Complex, Small Multi-Purpose Research Facility (SMiRF) recently completed validation / checkout testing of a new liquid methane delivery system and liquid methane (LCH4) conditioning system. Facility checkout validation was conducted in preparation for a series of passive thermal control technology tests planned at SMiRF in FY10 using a flight-like propellant tank at simulated thermal environments from 140 to 350K. These tests will validate models and provide high quality data to support consideration of LCH4/LO2 propellant combination option for a lunar or planetary ascent stage.An infrastructure has been put in place which will support testing of large amounts of liquid methane at SMiRF. Extensive modifications were made to the test facility s existing liquid hydrogen system for compatibility with liquid methane. Also, a new liquid methane fluid conditioning system will enable liquid methane to be quickly densified (sub-cooled below normal boiling point) and to be quickly reheated to saturation conditions between 92 and 140 K. Fluid temperatures can be quickly adjusted to compress the overall test duration. A detailed trade study was conducted to determine an appropriate technique to liquid conditioning with regard to the SMiRF facility s existing infrastructure. In addition, a completely new roadable dewar has been procured for transportation and temporary storage of liquid methane. A new spherical, flight-representative tank has also been fabricated for integration into the vacuum chamber at SMiRF. The addition of this system to SMiRF marks the first time a large-scale liquid methane propellant test capability has been realized at Glenn.This work supports the Cryogenic Fluid Management Project being conducted under the auspices of the Exploration Technology Development Program, providing focused cryogenic fluid management technology efforts to support NASA s future robotic or human exploration missions

ESS Target Moderator Cryogenic Plant : Process Design

The European Spallation Source (ESS) project is a neutron spallation source facility currently under construction outside Lund, Sweden. The ESS accelerator will deliver a 5 MW proton beam to a spallation target at 2.0 GeV with a nominal current of 62.5 mA to generate fast neutrons. The cooling of the spallation target with liquid hydrogen circulating in the cryogenic moderator system (CMS) transforms these fast neutrons to slow neutrons which compose the useful radiation. The liquid hydrogen itself is cooled by a helium refrigeration cycle, the target moderator cryogenic plant (TMCP) providing cooling capacity in a wide range of 2.3-31.8 kW at 15-20 K. TMCP\u27s maximum cooling capacity of 31.8 kW will make it the world\u27s largest plant of its kind. The TMCP project is challenging in many ways. The heat load of the CMS has to be removed precisely all the time by the TMCP. In addition the TMCP has to meet highly dynamic requirements as the heat load ceases quickly in case the proton beam trips off. Furthermore transitions within the wide cooling capacity range have to be achieved seamlessly. In this talk the progress of the TMCP engineering is summarized. Process design, control strategies, machine concept and layout are presented

Tank Applied Testing of Load-Bearing Multilayer Insulation (LB-MLI)

The development of long duration orbital cryogenic storage systems will require the reduction of heat loads into the storage tank. In the case of liquid hydrogen, complete elimination of the heat load at 20 K is currently impractical due to the limitations in lift available on flight cryocoolers. In order to reduce the heat load, without having to remove heat at 20 K, the concept of Reduced Boil-Off uses cooled shields within the insulation system at approximately 90 K. The development of Load-Bearing Multilayer Insulation (LB-MLI) allowed the 90 K shield with tubing and cryocooler attachments to be suspended within the MLI and still be structurally stable. Coupon testing both thermally and structurally were performed to verify that the LB-MLI should work at the tank applied level. Then tank applied thermal and structural (acoustic) testing was performed to demonstrate the functionality of the LB-MLI as a structural insulation system. The LB-MLI showed no degradation of thermal performance due to the acoustic testing and showed excellent thermal performance when integrated with a 90 K class cryocooler on a liquid hydrogen tank

Liquid hydrogen for cold neutron production at European Spallation Source ERIC

The European Spallation Source (ESS) will be a 5 MW, long-pulsed spallation neutron research facility. One of the key feature is that ESS will use liquid hydrogen as a moderating media for the cold neutrons. The hydrogen operates at cryogenic temperatures at approximately 17K. The challenge for the cryogenic system is to meet the high neutronic heat load and maintain a narrow operational span. To handle the large variations in heat load a special developed pressure control device is designed. To maintain the hydrogen operating temperature, a Helium refrigerator with unique capabilities to control temperature in the hydrogen system is developed. It also has the capacity to react and compensate for a lower heat load than anticipated in the moderator system on short notice. Another key feature is the Ortho-Para catalyst and the in line OP measurement that verifies the high para content at all time, to optimize neutronic performance. This paper describes the process development, planned commissioning and operation of the cryogenic hydrogen and ancillary systems

Spallation target cryogenic cooling design challenges at the European Spallation Source

The European Spallation Source (ESS) project is a neutron spallation source research facility currently being designed and built outside of Lund, Sweden. A linear accelerator delivers a 5 MW, 2.0 GeV, 62.5 mA proton beam to a spallation target to generate fast neutrons. Supercritical hydrogen circulates through two moderators surrounding the target, and transforms the fast neutrons emitted into slow neutrons, which are the final form of useful radiation. The supercritical hydrogen is in turn cooled from a helium cryogenic plant operating at 15-20 K. The supercritical cryogenic hydrogen circuit is a dynamic system, subject to significant changes in heat load. Proper pressure control of this system is critical to assure safe operation. The interaction between the hydrogen system and helium cryoplant poses unique challenges. This paper investigates the impact of the hydrogen system constraints on operation and control of the helium cryoplant, and suggests design options for the helium circuit