Tertiary flow injection thrust vectoring system Patent
Tertiary flow injection system for thrust vectoring of propulsive nozzle flow
Kepler, C. E.↗
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Flow Injection Electrochemical Quartz Crystal Microbalance with ICP-OES Detection: Electroprecipitation and Stripping of Lanthanum and Neodymium in a Flow Cell
We used an improved version of our hyphenated analysis technique, flow injection electrochemical quartz crystal microbalance (EQCM) with inductively coupled optical emission spectroscopy, to investigate the electroprecipitation of lanthanum and neodymium from flowing solutions. The improved version has two independent flow injection circuits, allowing different conditions for electrochemical precipitation (pH=4.3 or 2.6) and quick stripping (2% HNO3) with EQCM mass detection and ICP-OES elemental analysis. Lanthanum or neodymium ions in a 500 uL sample were injected into a carrier stream and deposited onto an EQCM housed in a micro flow cell, owing to a localized high-pH layer. The deposits are subsequently stripped from the electrode using HNO3 and analyzed downstream using an ICP-OES. We found that using acidic solutions without supporting electrolyte leads to an increase of the amount of lanthanum detected by 4-fold. The enhanced deposition can be attributed to enhanced mass transfer by migration. Furthermore, we showed that by applying chronopotentiometry, we can detect a change in the hydrogen evolution reaction mechanism that enables the precipitation of lanthanides on the surface of the electrode. Understanding and enhancing the deposition of lanthanides is relevant for elemental or isotopic detection in nuclear forensics.
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
Three-dimensional computations of cross-flow injection and combustion in a supersonic flow
A low-storage version of the SPARK3D code which is based on the temporally second-order accurate MacCormack (1969) explicit scheme is used to solve the governing equations for three-dimensional chemically reacting flows with finite-rate chemistry. The code includes a fourth-order compact spatial scheme capable of providing higher order spatial accuracy, and it is used to study two-dimensional linear advection, two-dimensional Euler flow, and three-dimensional viscous flow. Also considered are the injection, mixing, and combustion of hydrogen in a supersonic cross stream.
Carpenter, M. H.↗
Supersonic Mixing and Combustion in Parallel Injection Flow Fields
Adequate prediction techniques for supersonic, mixing, reacting flows are of great importance in the design and performance analysis of supersonic combustion ramjet (scramjet) engines. Analytical programs for parallel injection flow fields with chemical reaction and turbulent mixing are now available for both single and multiple-jet flows. The application of these analyses to simple flow geometries is discussed, and comparisons also are made with data on the more complex case of multiple-jet, reacting flows. A review is given of Langley investigations of parallel injection flow fields. Among these are single-jet studies of nonreacting, turbulent mixing (H2 in air and H2 in N2), and of reacting turbulent mixing (H2 in air) with both single and multiple jets. Implications of the results of the studies for scramjet fuel injector design are discussed.
Evans, J. S.↗
"Reagentless" flow injection determination of ammonia and urea using membrane separation and solid phase basification
Flow injection analysis instrumentation and methodology for the determination of ammonia and ammonium ions in an aqueous solution are described. Using in-line solid phase basification beds containing crystalline media. the speciation of ammoniacal nitrogen is shifted toward the un-ionized form. which diffuses in the gas phase across a hydrophobic microporous hollow fiber membrane into a pure-water-containing analytical stream. The two streams flow in a countercurrent configuration on opposite sides of the membrane. The neutral pH of the analytical stream promotes the formation of ammonium cations, which are detected using specific conductance. The methodology provides a lower limit of detection of 10 microgram/L and a dynamic concentration range spanning three orders of magnitude using a 315-microliters sample injection volume. Using immobilized urease to enzymatically promote the hydrolysis of urea to produce ammonia and carbon dioxide, the technique has been extended to the determination of urea.
NASA Center JSC↗
Flow Injection Electrochemical Quartz Crystal Microbalance with ICP-OES Detection: Recovery of Silver by Electrodeposition with Redox Replacement in a Flow Cell
We developed a new on-line hyphenated flow injection analysis technique (FI-EQCM-ICP-OES) that allows electrochemical deposition and stripping with mass detection and elemental analysis. This technique was used to study a new system for electrochemical recovery of silver from a 0.5 mM Ag + /5 mM Cu 2+ /0.5 M H 2 SO 4 solution by pulsed electrodeposition with redox replacement (EDRR) in a small flow cell. The metal ions in a 500 μ l sample are injected into the sulfuric acid carrier stream and deposited onto an electrochemical quartz crystal microbalance (EQCM) electrode housed in a 50 μ l flow cell. The deposits are subsequently stripped off electrochemically in the same cell and analyzed downstream in an ICP-OES. The stripped metal layer was found to be composed of Ag with no detectable Cu for a redox replacement time of 10 s, and 91 wt.% Ag–9 wt.% Cu for a redox replacement time of 5 s. Microscopy measurements demonstrated that the electrode was covered with silver particles, some of which contain Cu in the case of the 5 s replacement time. This technique allowed the study of mass changes on the electrode during electrodeposition and open circuit times in each EDRR cycle in flowing solutions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
A unified non-equilibrium phase change model for injection flow modeling
The homogenous relaxation model (HRM) is one of the most widely used models to describe the liquid- gas phase transition. However, in its original formulation, it is unable to handle multispecies vapor-liquid equilibrium (VLE), which limits its applicability to single-component fluids. In this work, a unified non-equilibrium phase change model that considers the VLE of multicomponent mixtures is proposed building upon the HRM's structure. A time factor is introduced to mimic the effect of different phase change timescales due to different mechanisms, e.g., cavitation, flash-boiling, and evaporation. Here to assess the model's performance, computational fluid dynamics simulations of the internal and near-nozzle injection flow of the Engine Combustion Network's Spray G injector were performed using the nine-component PACE-20 fuel with both the unified model and the original HRM. The predicted fuel density in the near-nozzle region matched well with X-ray tomography measurements. The simulation results indicated that, whereas the HRM failed to capture the vaporization due to convective mixing between the fuel and ambient gas, the unified model performed well in predicting the mixing-driven vaporization and the corresponding evaporative cooling. Further comparisons using the nine-component fuel formula and a single-component fuel surrogate demonstrated the unified model's ability to predict preferential vaporization, which affects the predictions of local mixture composition and rate of vaporization. Finally, it is shown that the unified model is capable of representing multiple phase change mechanisms, and the relaxation time factor plays an important role in determining the degree of phase change due to the different mechanisms.
33 ADVANCED PROPULSION SYSTEMS↗
Theoretical and experimental study of flow through turbine cascades with coolant flow injection
An analytical study is presented which deals with the change in the outlet flow conditions from a turbine blade row due to coolant air injection through slots. The analysis applies to small secondary to primary mass flow ratios, taking into consideration the change in boundary layer development resulting from injection. The effects of injection location, injection flow angle and injected air momentum flux are investigated. The results of the present analysis are compared with the values obtained using the mixing theory method and experimental data from cold flow tests in a turbine cascade tunnel.
Tabakoff, W.↗
Effect of Trailing Edge Flow Injection on Fan Noise and Aerodynamic Performance
An experimental investigation using trailing edge blowing for reducing fan rotor/guide vane wake interaction noise was completed in the NASA Glenn 9- by 15-foot Low Speed Wind Tunnel. Data were acquired to measure noise, aerodynamic performance, and flow features for a 22" tip diameter fan representative of modern turbofan technology. The fan was designed to use trailing edge blowing to reduce the fan blade wake momentum deficit. The test objective was to quantify noise reductions, measure impacts on fan aerodynamic performance, and document the flow field using hot-film anemometry. Measurements concentrated on approach, cutback, and takeoff rotational speeds as those are the primary conditions of acoustic interest. Data are presented for a 2% (relative to overall fan flow) trailing edge injection rate and show a 2 dB reduction in Overall Sound Power Level (OAPWL) at all fan test speeds. The reduction in broadband noise is nearly constant and is approximately 1.5 dB up to 20 kHz at all fan speeds. Measurements of tone noise show significant variation, as evidenced by reductions of up to 6 dB in the 2 BPF tone at 6700 rpm.: and increases of nearly 2 dB for the 4 BPF tone at approach speed. Aerodynamic performance measurements show the fan with 2 % injection has an overall efficiency that is comparable to the baseline fan and operates, as intended, with nearly the same pressure ratio and mass flow parameters. Hot-film measurements obtained at the approach operating condition indicate that mean blade wake filling in the tip region was not as significant as expected. This suggests that additional acoustic benefits could be realized if the trailing edge blowing could be modified to provide better filling of the wake momentum deficit. Nevertheless, the hot-film measurements indicate that the trailing edge blowing provided significant reductions in blade wake turbulence. Overall, these results indicate that further work may be required to fully understand the proper implementation of injecting flow at/near the trailing edge as a wake filling strategy. However, data do support the notion that noise reductions can be realized not only for tones but perhaps more importantly, also for broadband. Furthermore, the technique can be implemented without adversely effecting overall fan aerodynamic performance.
Fite, E. Brian↗
National Combustion Code Validated Against Lean Direct Injection Flow Field Data
Most combustion processes have, in some way or another, a recirculating flow field. This recirculation stabilizes the reaction zone, or flame, but an unnecessarily large recirculation zone can result in high nitrogen oxide (NOx) values for combustion systems. The size of this recirculation zone is crucial to the performance of state-of-the-art, low-emissions hardware. If this is a large-scale combustion process, the flow field will probably be turbulent and, therefore, three-dimensional. This research dealt primarily with flow fields resulting from lean direct injection (LDI) concepts, as described in Research & Technology 2001. LDI is a concept that depends heavily on the design of the swirler. The LDI concept has the potential to reduce NOx values from 50 to 70 percent of current values, with good flame stability characteristics. It is cost effective and (hopefully) beneficial to do most of the design work for an LDI swirler using computer-aided design (CAD) and computer-aided engineering (CAE) tools. Computational fluid dynamics (CFD) codes are CAE tools that can calculate three-dimensional flows in complex geometries. However, CFD codes are only beginning to correctly calculate the flow fields for complex devices, and the related combustion models usually remove a large portion of the flow physics.
Iannetti, Anthony C.↗
Static Flow Characteristics of a Mass Flow Injecting Valve
A sleeve valve is under development for ground-based forced response testing of air compression systems. This valve will be used to inject air and to impart momentum to the flow inside the first stage of a multi-stage compressor. The valve was designed to deliver a maximum mass flow of 0.22 lbm/s (0.1 kg/s) with a maximum valve throat area of 0.12 sq. in (80 sq. mm), a 100 psid (689 KPA) pressure difference across the valve and a 68 F, (20 C) air supply. It was assumed that the valve mass flow rate would be proportional to the valve orifice area. A static flow calibration revealed a nonlinear valve orifice area to mass flow relationship which limits the maximum flow rate that the valve can deliver. This nonlinearity was found to be caused by multiple choking points in the flow path. A simple model was used to explain this nonlinearity and the model was compared to the static flow calibration data. Only steady flow data is presented here. In this report, the static flow characteristics of a proportionally controlled sleeve valve are modelled and validated against experimental data.
Mattern, Duane↗
Co-flow injection for serial crystallography at X-ray free-electron lasers
Serial femtosecond crystallography (SFX) is a powerful technique that exploits X-ray free-electron lasers to determine the structure of macromolecules at room temperature. Despite the impressive exposition of structural details with this novel crystallographic approach, the methods currently available to introduce crystals into the path of the X-ray beam sometimes exhibit serious drawbacks. Samples requiring liquid injection of crystal slurries consume large quantities of crystals (at times up to a gram of protein per data set), may not be compatible with vacuum configurations on beamlines or provide a high background due to additional sheathing liquids present during the injection. Proposed and characterized here is the use of an immiscible inert oil phase to supplement the flow of sample in a hybrid microfluidic 3D-printed co-flow device. Co-flow generation is reported with sample and oil phases flowing in parallel, resulting in stable injection conditions for two different resin materials experimentally. A numerical model is presented that adequately predicts these flow-rate conditions. The co-flow generating devices reduce crystal clogging effects, have the potential to conserve protein crystal samples up to 95% and will allow degradation-free light-induced time-resolved SFX.
3D printing↗
Large Eddy Simulation of a Film Cooling Flow Injected from an Inclined Discrete Cylindrical Hole into a Crossflow with Zero-Pressure Gradient Turbulent Boundary Layer
A Large Eddy Simulation (LES) is performed of a high blowing ratio (M = 1.7) film cooling flow with density ratio of unity. Mean results are compared with experimental data to show the degree of fidelity achieved in the simulation. While the trends in the LES prediction are a noticeable improvement over Reynolds-Averaged Navier-Stokes (RANS) predictions, there is still a lack a spreading on the underside of the lifted jet. This is likely due to the inability of the LES to capture the full range of influential eddies on the underside of the jet due to their smaller structure. The unsteady structures in the turbulent coolant jet are also explored and related to turbulent mixing characteristics
Johnson, Perry L.↗
INVESTIGATION OF BOUNDARY LAYER PARAMETERS IN APG NOZZLE AND THE FLOW INTERFERENCE CAUSED BY SECONDARY INJECTION
Flow interference caused by secondary injection in adverse pressure gradient nozzles - boundary layer parameter investigations
GAS FLOW↗
Numerical Investigation of Flow Around Rectangular Cylinders with and Without Jets
The problem of flow past bluff bodies was studied extensively in the past. The problem of drag reduction is very important in many high speed flow applications. Considerable work has been done in this subject area in case of circular cylinders. The present study attempts to investigate the feasibility of drag reduction on a rectangular cylinder by flow injection by flow injection from the rear stagnation region. The physical problem is modeled as two-dimensional body and numerical analysis is carried out with and without trailing jets. A commercial code is used for this purpose. Unsteady computation is performed in case of rectangular cylinders with no trailing jets where as steady state computation is performed when jet is introduced. It is found that drag can be reduced by introducing jets with small intensity in rear stagnation region of the rectangular cylinders.
Tiwari, S. N .↗
An experimental investigation of thrust vector control by secondary injection
Flow field produced by secondary gas injection into supersonic primary stream
SECONDARY INJECTION↗
Systems and methods for geothermal energy storage
A method and system may be used for storing energy in a geothermal system and recovering both the stored energy as well as thermal energy on demand. The geothermal system may include injection and production wells that are hydraulically coupled in a geothermal energy reservoir that behaves as a confined reservoir system with thermal energy transferring to fluid injected into the injection well and removed via the production well. Injection flow rate, injection pressure, production flow rate, production backpressure, or fluid residence time may be managed to control energy consumption or energy generation profiles of the geothermal system. During an energy storage mode, the injection flow rate exceeds the production flow rate thereby storing energy in the geothermal reservoir. During an energy recovery mode, production backpressure is reduced thereby releasing the stored energy and electricity is generated by removing the thermal energy from the fluid in a heat engine.
Norbeck, Jack↗