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Two-phase flow and heat transfer is an important technology for future development of interplanetary spacecraft thermal control, planetary-based power generation systems, and hypersonic vehicle thermal protection. This paper presents several analytical considerations for the prediction of two-phase flow and heat transfer. Two specific examples are explained; the first is that of two-phase natural convection and the second is that of an evaporating two-phase flow.

For long-duration space missions, the life support and In-Situ Resource Utilization (ISRU) systems necessary to lower the mass and volume of consumables carried from Earth will require more sophisticated chemical processing technologies involving gas-liquid two-phase flows. This paper discusses some preliminary two-phase flow work in packed columns and generation of bubbly suspensions, two types of flow systems that can exist in a number of chemical processing devices. The experimental hardware for a co-current flow packed column operated in two ground-based low gravity facilities (two-second drop tower and KC-135 low-gravity aircraft) is described. The preliminary results of this experimental work are discussed. The flow regimes observed and the conditions under which these flow regimes occur are compared with the available co-current packed column experimental work performed in normal gravity.

Aspects of the gravitational scaling of spacecraft two-phase heat transport systems are discussed. Supporting similitude considerations, based on dimension analysis, and useful equations and correlations are given.

Based on the thermal requirements of future large European platforms such as the Columbus Space Station, several developments in the field of two-phase flow systems were initiated over the last few years in Europe. This paper will give a general overview of the objectives, development status and test results of an ESA-funded ‘Two-phase heat transport system’ study and of two studies sponsored by the German Ministry of Research and Technology on two-phase heat transport. The ESA two-phase loop system resulting from the concept trade-off is driven by an electrically powered liquid pump and is provided with a capillary cold plate and an evaporative heat exchanger mounted in parallel. Under certain conditions, a simplified version of this type of system is able to work in a capillary-pumped mode. The system is designed for a heat load of 10-20 KW, a length of 20 m, a working temperature around 20°C and R114 as working fluid.

This paper describes advanced heat acquisition and transport components developed and tested as part of the Two-Phase Survivable Thermal Management (TSTM) Program. The components are: a pumped heat pipe coldplate capable of removing very high-flux waste heat loads with a minimum temperature drop; and a thermal transport system designed to transport large quantities of waste heat over large distances with a long life and low power consumption. These components are intended for use in an advanced thermal control system which removes waste heat from high-power spacecraft. For the heat acquisition component, a successful design development phase was completed, resulting in a producible design which met program goals. This design was subjected to extensive tests to demonstrate performance under a wide variety of conditions. The component was found to perform in a predictable manner. Measured overall component thermal conductance was 4.0 W/cm2/°C for fluxes up to 60 W/cm2.

Simultaneous thermal and hydraulic analysis has been completed using SINDA'85/FLUINT for a two-phase ammonia thermal control system proposed for Space Station Freedom Attached Payload Accommodation Equipment (APAE). This analysis provided information on system performance, transient behavior during heat load changes, and control system response. Control system logic and non-equilibrium effects were included in the model. This paper describes the hardware used in this thermal control system and the modelling techniques used to represent it. A brief comparison of the predicted system performance with test results from ground testing of similar systems at NASA Johnson Space Center is also provided.

Discussed are some critical theoretical and experimental research issues to be investigated for candidate two-phase thermal control systems (and their components), to define what is to be done to develop reliable systems, for near and far future planetary applications envisaged. An earlier publication SAE-2007-01-3242 (“Design of planetary two-phase thermal control systems, using experimental data of terrestrial model systems, built according to thermal-gravitational modelling and scaling laws”), discussed that such advanced thermal control systems are one of the key technologies needed for future applications within the framework of the NASA Authorization Act 2005. This act specifies a programme to be established to develop sustained human presence on the Moon, including a robust pre-curser programme to promote exploration, science, commerce and US preeminence in space, also as a stepping stone to future exploration of Mars and other planetary destinations.

This paper gives a general overview of the objectives of European two-phase heat transport systems as well as of their development status. In particular the actual design of the ESA funded development program “Two-Phase Heat Transport Systems - Critical Components” will be shown. Results are also reported on an extensive program of development of heat absorbing components for an application in two-phase thermal systems sponsored by the German Ministry of Research and Technology. The objectives of this project were to design, manufacture and test three types of evaporators or cold plates, two of them designed for an application in a mechanically pumped loop and one foreseen to operate as evaporative capillary pump in a capillary pumped loop. Finally a short outlook is given on the planned future European two-phase development activities.

Many diesel engines have to work at load profiles which, due to the low exhaust gas temperatures, necessitate active regeneration procedures to ensure continued engine operation and the reliability of the particulate filter. An active regeneration may be initiated via inner engine measures such as late injection. However, due to high maintenance interval and run time requirements for non-road applications the combustion of soot accumulated in the diesel particulate filter (DPF) often is realized via downstream processes. Known methods for this purpose are burner systems, systems based on downstream hydrocarbon injection (HCI) and subsequent hydrocarbon (HC)-conversion due to a catalyst or a combination of both. This paper describes an autarkic system using two-stage electro-thermal-supported hydrocarbon conversion. This system is capable to regenerate a DPF within the entire engine operating range and it is less complex than flame burner systems.

The Wave Disk Engine (WDE) is a novel engine that has the potential for higher efficiency and power density of power-generation systems. A recent version of wave disk engine architecture known as the two-stage WDE has been studied to address existing challenges of an existing WDE. After describing the engine operation, a cold air-standard thermodynamic model supporting the physical phenomena occurring inside the device is introduced to evaluate performance of the engine. The developed model is general and does not depend on the shape of the wave rotor, it can be applied to radial and axial combustion wave rotors integrated with turbomachinery devices. The analysis starts with predicting internal waves propagating inside the channels of the engine and linking various flow states to each other using thermodynamics relationships. The goal is to find analytical expressions of work output and efficiency in terms of known pressure and temperature ratios.

The current position of the two-stroke cycle aircraft engine is described with respect to competitive type powerplants, including a brief historical background and information on some of the latest designs. The two-cycle case is substantiated with arguments and data showing why it should still be considered for the lower power ranges.

Numerous turbofan power-loss events have occurred in high altitude locations in the presence of ice crystals. It is theorized that ice crystals enter the engine core, partially melt in the compressor and then accrete onto stator blade surfaces. This may lead to engine rollback, or shed induced blade damage, surge and/or flameout. The first generation of ice crystal icing predictive models use a single flow field where there is no accretion to calculate particle trajectories and accretion growth rates. Recent work completed at the University of Oxford has created an algorithm to automatically detect the edge of accretion from experimental video data. Using these accretion profiles, numerical simulations were carried out at discrete points in time using a manual meshing process.

Deicing the aircraft using fluid, prior takeoff is mandatory; since a thin layer of ice or snow can compromise the safety. With the same idea, to use anti-icing fluid during a frozen precipitation to protect the aircraft is also essential. Commercialized anti-icing fluids all pass the process of qualification as described in the SAE documents. One of these documents specifies a set of tests that reproduce freezing precipitation to obtain endurance time and then the holdover timetables. The endurance time is determined by visual inspection: when 30% of the plate is covered with frozen contaminants. With the evolution of technology and the venue of new tools, it may simplify the process, and at least confirm the observations. This paper proposed a thermal and visual analysis of the behavior of a Type IV fluid subjected to light freezing rain. During the precipitation, the plate temperature is measured with thermocouples and recorded using a visual camera and an IR camera.

Measurements of lightning-induced transients in typical electrical circuits installed within a small, conventional aluminum airplane fuselage have been made as part of a comprehensive assessment of the effects of direct lightning strikes and high intensity radiated frequency (HIRF) fields on avionic systems installed within small aircraft. These measurements were conducted in support of development of design guidelines for installation and certification of advanced avionics in small aircraft, under a U.S. National Aeronautics and Space Administration (NASA) sponsored Small Business Innovation Research (SBIR) program aimed at developing technology to enable advanced avionic systems to be installed in new small airplanes or to be retrofitted into existing airplanes. This paper presents examples and summaries of lightning-related magnetic fields and resulting induced voltage and current transients within a small 4-place Mooney aluminum fuselage and engine nacelle.

Voice technology provides a potential for alleviating the extremely high visual and manual workload of Army helicopter pilots. Before voice technology can be successfully employed in the cockpit, there are many human factors issues that must be resolved. This paper describes the approach used to identify potential applications of voice technology in an Army helicopter and the emulation of a voice interactive doppler navigation set.

The General Aviation safety record through 1970 is discussed, both statistically and in the non-quantitative sense. Related functions of the cognizant aviation accident investigatory agency, the National Transportation Safety Board, are also reviewed to place the data in proper perspective. Finally, a matrix is provided as an outline for participants in the General Aviation system to assess their own contribution to accident/injury prevention in this most rapidly growing segment of aviation.

In order to formulate policy for the orderly development and use of the nation's navigable air space, federal agencies such as the FAA and the Department of Transportation have launched several programs to determine aviation requirements for the next 10 years. This paper outlines their conclusions concerning airborne activities such as flow control, approach and departure control, wake vortex problems, and operating procedures as well as airport capacity and ground operations. The impact of the FAA's Research and Development Program and the implications of the current fuel shortage and economic situation are also discussed.

This paper reviews research work in the United Kingdom on the objective effects of the sonic boom on humans and structures, and the subjective response of humans. Works in these areas, both before and during the Concorde aircraft's supersonic overflights, is described and appropriate references cited.

For the last several years, the Soviet Union, now the Commonwealth of Independent States (CIS), has offered the RD-170 rocket engine for sale to the West. The RD-170 is the most powerful and most technologically advanced rocket engine in production in the world. However, the U.S. presently has no policy regarding the acquisition of Soviet rocket technology such as the RD-170. In order to develop an effective policy, the U.S. must first determine if an application for RD-170 class engines exists, and then weigh the advantages of acquisition such as reliable and cost effective heavy lift capability versus the disadvantages such as exporting U.S. jobs. There are several possible methods of acquisition, although joint U.S.-CIS production of the RD-170 is the most politically viable as it would create U.S. jobs and support economic reforms in the CIS at the same time.