Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “hot injection”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

456 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Benchmark Wall Heat Flux Data for a GO2/GH2 Single Element Combustor

Wall heat flux measurements in a 1.5 in. diameter circular cross-section rocket chamber for a uni-element shear coaxial injector element operating on gaseous oxygen (GOz)/gaseous hydrogen (GH,) propellants are presented. The wall heat flux measurements were made using arrays of Gardon type heat flux gauges and coaxial thermocouple instrumentation. Wall heat flux measurements were made for two cases. For the first case, GOZ/GHz oxidizer-rich (O/F=l65) and fuel-rich preburners (O/F=1.09) integrated with the main chamber were utilized to provide vitiated hot fuel and oxidizer to the study shear coaxial injector element. For the second case, the preburners were removed and ambient temperature gaseous oxygen/gaseous hydrogen propellants were supplied to the study injector. Experiments were conducted at four chamber pressures of 750, 600, 450 and 300psia for each case. The overall mixture ratio for the preburner case was 6.6, whereas for the ambient propellant case, the mixture ratio was 6.0. Total propellant flow was nominally 0.27-0.29 Ibm/s for the 750 psia case with flowrates scaled down linearly for lower chamber pressures. The axial heat flux profile results for both the preburner and ambient propellant cases show peak heat flux levels a t axial locations between 2.0 and 3.0 in. from the injector face. The maximum heat flux level was about two times greater for the preburner case. This is attributed to the higher injector fuel-to-oxidizer momentum flux ratio that promotes mixing and higher initial propellant temperature for the preburner case which results in a shorter reaction zone. The axial heat flux profiles were also scaled with respect to the chamber pressure to the power 0.8. The results at the four chamber pressures for both cases collapsed to a single profile indicating that at least to first approximation, the basic fluid dynamic structures in the flow field are pressure independent as long as the chamber/njector/nozzle geometry and injection velocities remain the same.

Marshall, William M.↗
DOE OSTI2021

Machine Learning to Identify Geologic Factors Associated with Production in Geothermal Fields: A Case-Study Using 3D Geologic Data from Brady Geothermal Field and NMFk

In this paper, we present an analysis using unsupervised machine learning (ML) to identify the key geologic factors that contribute to the geothermal production in Brady geothermal field. Brady is a hydrothermal system in northwestern Nevada that supports both electricity production and direct use of hydrothermal fluids. Transmissive fuid-fow pathways are relatively rare in the subsurface, but are critical components of hydrothermal systems like Brady and many other types of fuid-fow systems in fractured rock. Here, we analyze geologic data with ML methods to unravel the local geologic controls on these pathways. The ML method, non-negative matrix factorization with k-means clustering (NMFk), is applied to a library of 14 3D geologic characteristics hypothesized to control hydrothermal circulation in the Brady geothermal field. Our results indicate that macro-scale faults and a local step-over in the fault system preferentially occur along production wells when compared to injection wells and non-productive wells. We infer that these are the key geologic characteristics that control the through-going hydrothermal transmission pathways at Brady. Our results demonstrate: (1) the specific geologic controls on the Brady hydrothermal system and (2) the efficacy of pairing ML techniques with 3D geologic characterization to enhance the understanding of subsurface processes. This submission includes the published journal article detailing this work, the published 3D geologic map of the Brady Geothermal Area used as a basis to develop structural and geological variables that are hypothesized to control or effect permeability or connectivity, 3D well data, along which geologic data were sampled for PCA analyses, and associated metadata file. This work was done using the GeoThermalCloud framework, which is part of SmartTensors (both are linked below).

15 GEOTHERMAL ENERGY↗
NASA NTRS2010

Current Status of NASA's Heavy Lift Plans

Numerous studies since the Apollo Program of the 1960s have highlighted the benefits of - and the need for - a national heavy lift launch capability to support human exploration, science, national security, and commercial development of space. NASA's most recent and most refined effort to develop that heavy lift capability is the Ares V. Ares V is a key element of NASA's Constellation Program. It s overall goal s part of approved national space policy is to retire the Space Shuttle and develop its successor, complete the International Space Station, and resume human exploration beyond low Earth orbit (LEO), beginning with exploration of the Moon as a step to other destinations in the Solar System. Ares V s first role is that of cargo vehicle to carry a lunar lander into Earth orbit, rendezvous with astronauts launched on the smaller Ares I crew launch vehicle, and perform the trans lunar injection (TLI) mission to send the mated crew and lander vehicles to the Moon. The design reference missions (DRMs) envisioned for it also include direct lunar cargo flights and a human Mars mission. Although NASA's priority from the start of the Constellation Program to the present has been development of the Ares I and Orion crew vehicle to replace the retiring Shuttle fleet, the Ares team has made significant progress in understanding the performance, design trades, technology needs, mission scenarios, ground and flight operations, cost, and other factors associated with heavy lift development. The current reference configuration was selected during the Lunar Capabilities Concept Review (LCCR) in fall 2008. That design has served since then as a point of departure for further refinements and trades among five participating NASA field centers. Ares V development to date has benefited from progress on the Ares I due to commonality between the vehicles. The Ares I first stage completed a successful firing of a 5-segment solid rocket motor. The Ares I-X launch Numerous studies since the Apollo Program of the 1960s have highlighted the benefits of and the need for - a national heavy lift launch capability to support human exploration, science, national security, and commercial development of space. NASA s most recent and most refined effort to develop that heavy lift capability is the Ares V. Ares V is a key element of NASA s Constellation Program. It s overall goal s part of approved national space policy is to retire the Space Shuttle and develop its successor, complete the International Space Station, and resume human exploration beyond low Earth orbit (LEO), beginning with exploration of the Moon as a step to other destinations in the Solar System. Ares V s first role is that of cargo vehicle to carry a lunar lander into Earth orbit, rendezvous with astronauts launched on the smaller Ares I crew launch vehicle, and perform the trans lunar injection (TLI) mission to send the mated crew and lander vehicles to the Moon. The design reference missions (DRMs) envisioned for it also include direct lunar cargo flights and a human Mars mission. Although NASA s priority from the start of the Constellation Program to the present has been development of the Ares I and Orion crew vehicle to replace the retiring Shuttle fleet, the Ares team has made significant progress in understanding the performance, design trades, technology needs, mission scenarios, ground and flight operations, cost, and other factors associated with heavy lift development. The current reference configuration was selected during the Lunar Capabilities Concept Review (LCCR) in fall 2008. That design has served since then as a point of departure for further refinements and trades among five participating NASA field centers. Ares V development to date has benefited from progress on the Ares I due to commonality between the vehicles. The Ares I first stage completed a successful firing of a 5-segment solid rocket motor. The Ares I-X launch successfully demonstrated in suborbital flighhe ability to assemble, prepare, launch, control and recover the Ares I configuration and compare performance to computer models. Component tests continue on the J-2X engine, which will put both the Ares I and Ares V upper stages into orbit. In addition, more than 100,000 parts have been manufactured or on the assembly line for the first J-2X powerpack and the first two development engines, with hot fire tests to begin in 2011. This paper will further detail the progress to date on the Ares V and planned activities for the remainder of 2010. In addition, the Ares V team has continued its outreach to potential user communities in science and national security. Through the Constellation Program, NASA has amassed an enormous knowledge base in the design, technologies, and operations of heavy lift launch vehicles that will be a national asset for any future launch vehicle decision. This early phase of the design presents the best opportunity to incorporate where possible the insights and needs of other users.

Creech, Steve↗
NASA NTRSDate not supplied

Numerical Investigation of the Effect of Cooling Airflow inside High-Pressure Turbine using the Source Term Approach

In this study, the Open National Combustion code (OpenNCC) is applied to simulate the airflow inside the high-pressure turbine (HPT) of the energy efficient engine (EEE). The main objective of this study is to compare the characteristics of the HPT performance obtained by using three different approaches (Case 1: the realistic combustion products are considered at the HPT inlet, but the cooling airflows are not included, Case 2: the working fluid is assumed to be a single gas (i.e., air), and the cooling airflows are considered, Case 3: the cooling airflow and the combustion products at the HPT inlet are included). To mimic the cooling airflows at the HPT surface, we use the surface source team approach, in which we impose the source term at a specific area of a cooling airflow hole at the solid surfaces by specifying an injection angle, temperature, turbulent intensity, and mass flowrate of each cooling airflow. For the validation of the model, the data for the EEE model was obtained from the General Electric (GE) test campaign (RDG10), and the full scale warm-air rig test condition representing a test point close to the integrated core/low spool design condition was considered. This validation test was done using the stationary uniform inflow condition (i.e., the reported total temperature and total pressure). Secondly, we considered the Sea-Level Take-off (SLTO) engine condition and separately performed the combustor simulation to obtain a more realistic time-averaged, spatially-nonuniform HPT inflow condition. This work provides a better understanding the effect of the cooling airflow model with different assumptions on the HPT performance. It is found that using different working gas have a minor effect on the performance metric, however the presence of the cooling airflows significantly affects the HPT performance such as the turbine efficiency.

CFD Hot-streaks↗
NASA NTRSDate not supplied

NASA's Space Launch System Begins Integration, Stacking in Preparation for Artemis I Launch

The Artemis era of human lunar exploration is nearing take-off as NASA’s new super heavy-lift launch vehicle, the Space Launch System (SLS), begins stack-ing and integration operations in mid-2020 at Kennedy Space Center (KSC) in Florida. With a planned upgrade path to progressively more powerful vehicles and availability in crew and cargo configurations, SLS provides a unique and flexible launch solution to send crew, large-scale infrastructure and robotic probes to deep space. The SLS Block 1 vehicle, the initial variant to fly, is optimized for lunar missions with a proven propulsion system consisting of four liquid hydrogen (LH2)/liquid oxygen (LOX)-fed RS-25 engines and twin five-segment solid rocket boosters (SRBs). The Block 1 vehicle can also be outfitted with an industry-standard 5 m-class payload fairing (the “cargo” configuration) and will launch at least 27 metric tons (t) of mass to trans-lunar injection (TLI). SLS is the backbone of NASA’s Artemis program, which will return the agency’s human spaceflight program to the Moon for the first time since 1972. For the Artemis I mission, SLS will send an uncrewed Orion spacecraft to TLI, where it will enter a distant retrograde lunar orbit and fly 38,000 nmi past the Moon – farther than any spacecraft built for humans has ever traveled. The SLS Block 1 vehicle for Artemis I completed manufacturing in 2019. Several elements, including the upper stage, have been delivered to the Exploration Ground Systems (EGS) program at KSC and are being prepped for integration and stack-ing. The five-segment solid rocket boosters – the largest and most powerful ever built for flight – are also complete. The booster motor segments for the Artemis I flight are scheduled to ship from prime contractor Northrop Grumman’s Utah facilities and begin stacking and integration at KSC in June 2020. The SLS core stage is the largest rocket stage NASA has ever built in terms of volume and height, and includes the avionics and the tanks that feed cryogenic propellant to the four RS-25s (formerly Space Shuttle Main Engines [SSMEs]). They have been modified with an updated controller and nozzle insulation to protect them from the hotter launch environment. The SLS core stage is currently being test-ed at NASA’s Stennis Space Center (SSC) in a series of “green run” tests to verify it meets design and performance requirements. Following the green run test series, which is scheduled to culminate with a full-duration hot-fire of the four RS-25 engines, the core stage will ship to KSC and be stacked between the sol-id rocket boosters in the Vehicle Assembly Building (VAB). Integration of the vehicle will continue with the upper stage, known as the Interim Cryogenic Propulsion Stage (ICPS) and the Launch Vehicle Stage Adapter (LVSA) on the core stage. Another adapter, the Orion Stage Adapter (OSA), connects SLS to Orion and provides housing for 13 6U CubeSat payloads manifested on Artemis I. The CubeSats will be released in deep space after Orion separates from the vehicle, and the flight marks the first ride share opportunity for independent small-sats to deep space. The second major SLS variant to come online, Block 1B, replaces the single-engine ICPS with a four-engine LH2/LOX Exploration Upper Stage (EUS). This more powerful upper stage, along with other vehicle up-grades, will enable the Block 1B vehicle to launch 38-42 t to TLI, depending on crew or cargo configuration. The final evolution of the vehicle, Block 2, will onramp evolved solid rocket boosters to increase mass to TLI to 43-46 t, de-pending on crew or cargo configuration. The Block 1B/Block 2 vehicles can be outfitted with an 8.4 m-diameter payload fairing in 19.1 m or 27.4 m lengths, to provide unprecedented volume for payloads. With the initial Block 1 vehicle completely manufactured and the core stage in final testing before shipping to KSC, the SLS Program and its industry partners have made significant progress manufacturing subsequent vehicles. For the second Block 1 vehicle, the solid rocket motor segments are complete, as are the RS-25 engines with controllers. All five major components of the Artemis II core stage – the forward skirt, LOX and LH2 tanks, intertank and engine section – are manufactured and technicians are installing subsystems at NASA’s rocket factory, Michoud Assembly Facility. The RL-10 engine for the Artemis II ICPS is complete and panels have been machined for its LH2 tank. In addition, panels are machined for the vehicle’s two adapters, with welding scheduled to begin in summer 2020. Flight hard-ware is also in production for the third SLS vehicle, with several booster motor segments cast. The pace of development on the EUS has increased, with the goal to complete Critical Design Review (CDR) in December 2020. Several EUS test rings have been machined at Michoud. The EUS is designed to exe-cute a variety of missions – human spaceflight, deployment of deep-space infra-structure, or high-C3 missions to the outer solar system – with crew and cargo configurations available beginning in the mid-2020s. The near-term goal for the nation’s powerful new space exploration asset, however, is to launch the Arte-mis program, and send the first woman and the next man to the lunar surface. At the Astrodynamics Specialist Conference, the SLS program will update the community on the progress of the initial Block 1 vehicle in final green run test-ing, integration and stacking. In addition, this paper will provide an update to the community on the manufacturing status of subsequent Block 1 and Block 1B vehicles.

Steve Creech↗
NASA NTRS1994

Experimental studies of transpiration cooling with shock interaction in hypersonic flow, part B

This report describes the result of experimental studies conducted to examine the effects of the impingement of an oblique shock on the flowfield and surface characteristics of a transpiration-cooled wall in turbulent hypersonic flow. The principal objective of this work was to determine whether the interaction between the oblique shock and the low-momentum region of the transpiration-cooled boundary layer created a highly distorted flowfield and resulted in a significant reduction in the cooling effectiveness of the transpiration-cooled surface. As a part of this program, we also sought to determine the effectiveness of transpiration cooling with nitrogen and helium injectants for a wide range of blowing rates under constant-pressure conditions in the absence of shock interaction. This experimental program was conducted in the Calspan 48-Inch Shock Tunnel at nominal Mach numbers of 6 and 8, for a Reynolds number of 7.5 x 10(exp 6). For these test conditions, we obtained fully turbulent boundary layers upstream of the interaction regions over the transpiration-cooled segment of the flat plate. The experimental program was conducted in two phases. In the first phase, we examined the effects of mass-addition level and coolant properties on the cooling effectiveness of transpiration-cooled surfaces in the absence of shock interaction. In the second phase of the program, we examined the effects of oblique shock impingement on the flowfield and surface characteristics of a transpiration-cooled surface. The studies were conducted for a range of shock strengths with nitrogen and helium coolants to examine how the distribution of heat transfer and pressure and the characteristics of the flowfield in the interaction region varied with shock strength and the level of mass addition from the transpiration-cooled section of the model. The effects of the distribution of the blowing rate along the interaction regions were also examined for a range of blowing rates through the transpiration-cooled panels. The regions of shockwave/boundary layer interaction examined in these studies were induced by oblique shocks generated with a sharp, flat plate, inclined to the freestream at angles of 5 degrees, 7.5 degrees, and 10 degrees. It was found that, in the absence of an incident shock, transpiration cooling was a very effective method for reducing both the heat transfer and the skin friction loads on the surface. The helium coolant was found to be significantly more effective than nitrogen, because of its low molecular weight and high specific heat. The studies of shock-wave/transpiration-cooled surface interaction demonstrated that the interaction region between the incident shock and the low-momentum transpiration-cooled boundary layer did not result in a significant increase in the size of attached or separated interaction regions, and did not result in significant flowfield distortions above the interaction region. The increase in heating downstream of the shock-impingement point could easily be reduced to the values without shock impingement by a relatively small increase in the transpiration cooling in this region. Surprisingly, this increase in cooling rate did not result in a significant increase in size of the region ahead of the incident shock or create a significantly enlarged interaction region with a resultant increase in the distortion level in the inviscid flow. Thus, transpiration cooling appears to be a very effective technique to cool the internal surfaces of scramjet engines, where shocks in the engine would induce large local increases in wall heating and create viscous/inviscid interactions that could significantly disturb the smooth flow through the combustor. However, if hydrogen is used as the coolant, burning upstream of shock impingement might result in localized hot spots. Clearly, further research is needed in this area.

Holden, Michael S.↗