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Wind Tunnel Study of the Influence of Orifice Geometry and Flow Rates on the Measured Pressure Error of a Static Pressure Probe at Mach 3

Description: Abstract: Tests were conducted in the Jet Propulsion Laboratory's 20-inch Supersonic Wind Tunnel to determine the effect of hole-spacing geometry on the measured pressure error due to "breathing" for a pressure-sensing probe at Mach 3.01.
Date: November 1960
Creator: Zumwalt, G. W.
Partner: UNT Libraries Government Documents Department

Measurement of Static Pressure on Aircraft

Description: "Existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents are presented. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is inclined to flow. Errors which result from variations in the configuration of static-pressure vents are also presented" (p. 645).
Date: December 17, 1956
Creator: Gracey, William
Partner: UNT Libraries Government Documents Department

Fast pressure measurements of the local island divertor on the compact helical system

Description: Development of an effective divertor is critical for the viability of the stellarator (helical system) concept. In the local island divertor (LID) concept particle and heat fluxes are channeled to the back of the LID head by the magnetic field structure of an externally produced m = 1, n = I island that is outside the last closed flux surface. The leading edge of the LID head is protected from the outward heat flux from the plasma because it is located inside the 1/1 island and the particles that strike the target plates on the back of the LID head in the throat of the LID pump module are then pumped efficiently. A set of 16 coils was used to create a 1/1 island in the Compact Helical System (CHS). The current (I{sub LID}) in the LID coils was chosen to position either the 0-point or the X-point of the external 1/1 magnetic island at the location of the LID head. The principal diagnostic in this study was an ASDEX-style ionization gauge that allowed fast ({approx}1-ms) measurements of the neutral pressure buildup behind the divertor head in the LID module.
Date: August 1, 1997
Creator: Lyon, J.F.; Klepper, C.C. & England, A.C.
Partner: UNT Libraries Government Documents Department

Geysering discharge of a geothermal wellbore at Zunil, Guatemala

Description: Within two hours after discharge began, for a production test in 1989 of well ZCQ-4, pressure variations changed from approximately sinusoidal to a cycle of sudden and complex peak discharge pressures, to 9 bar, separated by irregular pressure declines to 5 bar. Initial cycle periods of 42 minutes evolved to 150 minutes by day 20 of continuous testing, when three of four surge peaks were well separated. Chemical signatures of fluids discharged with pressure surges were distinctive. When combined with downwell pressure measurements, assignments can be made for elevations of fluid entry points. The variety of chemical signatures indicates a scarcity of interzone connectivity. These constrained discharges are suspected to derive from altered rubble zones between layered volcanic rocks.
Date: January 1, 1991
Creator: Michels, Donald E.
Partner: UNT Libraries Government Documents Department


Description: PETN is widely recognized as an example of nearly ideal detonation performance. The chemical composition is such that little or no carbon is produced in the detonation products. The reaction zone width is less than currently detectable. (<1 ns) Observations on PETN have thus become a baseline for EOS model predictions. It has therefore become important to characterize the detonation parameters as accurately as possible in order to provide the most exacting comparisons of EOS predictions with experimental results. We undertook a painstaking review of the detonation pressure measurements reported in an earlier work that was presented at the Fifth Detonation Symposium and found that corrections were required in determining the shock velocity in the PMMA witness material. We also refined the impedance calculation to account for the difference between the usual ''acoustic'' method and the more accurate Riemann integral. Our review indicates that the CJ pressures previously reported for full density PETN require an average lowering of about 6 percent. The lower densities require progressively smaller corrections. We present analysis of the records, supporting hydrodynamic simulations, the Riemann integral results, and EOS parameter values derived from the revised results.
Date: June 23, 2006
Creator: Green, L. G. & Lee, E. L.
Partner: UNT Libraries Government Documents Department

An Analysis of Accumulator Ring Pressure Date

Description: This note summarizes and analyzes the Accumulator Ring's pressure data taken during the recent commissioning run (March-October, 1985) and during the three week interval immediately after the end of the commissioning run. Emphasis is placed upon the questions raised in reference [1], viz.: (1) What is the ultimate vacuum attainable? (2) How do we calculate the 'effective-pressure' for beam lifetime estimates from the ion gauge data? (3) What is the required sublimation schedule to maintain adequate vacuum?
Date: January 9, 1986
Creator: Gormley, M.
Partner: UNT Libraries Government Documents Department


Description: The first nondestructive examination (NDE) of 3013-type containers as part of the Department of Energy's (DOE's) Integrated Surveillance Program (ISP) was performed in February, 2005. Since that date 280 NDE surveillances on 255 containers have been conducted. These containers were packaged with plutonium-bearing materials at multiple DOE sites. The NDE surveillances were conducted at Hanford, Lawrence Livermore National Laboratory (LLNL), and Savannah River Site (SRS). These NDEs consisted of visual inspection, mass verification, radiological surveys, prompt gamma analysis, and radiography. The primary purpose of performing NDE surveillances is to determine if there has been a significant pressure buildup inside the inner 3013 container. This is done by measuring the lid deflection of the inner 3013 container using radiography images. These lid deflection measurements are converted to pressure measurements to determine if a container has a pressure of a 100 psig or greater. Making this determination is required by Surveillance and Monitoring Plan (S&MP). All 3013 containers are designed to withstand at least 699 psig as specified by DOE-STD-3013. To date, all containers evaluated have pressures under 50 psig. In addition, the radiography is useful in evaluating the contents of the 3013 container as well as determining the condition of the walls of the inner 3013 container and the convenience containers. The radiography has shown no signs of degradation of any container, but has revealed two packaging anomalies. Quantitative pressure measurements based on lid deflections, which give more information than the 'less than or greater than 100 psig' (pass/fail) data are also available for many containers. Statistical analyses of the pass/fail data combined with analysis of the quantitative data show that it is extremely unlikely that any container in the population of 3013 containers considered in this study (e.g., containers packaged according to the DOE-STD-3013 by 2006) would exceed a pressure ...
Date: February 1, 2010
Creator: Yerger, L.; Mcclard, J.; Traver, L. & Grim, T.
Partner: UNT Libraries Government Documents Department


Description: The Can Puncture Device (CPD) serves as a containment vessel during the puncture of nested 3013 containers as part of surveillance operations in K-Area. The purpose of the CPD sampling process is to determine the original pressure and composition of gases within the inner 3013 container. The relation between the composition of the gas sample drawn from the CPD and that originally in the inner 3013 container depends on the degree of mixing that occurs over the interval of time from the puncture to drawing the sample. Gas mixing is bounded by the extremes of no mixing of gases in the inner container and that of complete mixing, in which case the entire CPD system is of uniform composition. Models relating the sample composition and pressure to the initial (pre-puncture) inner can composition and pressure for each of these extremes were developed. Predictions from both models were compared to data from characterization experiments. In the comparison, it was found that the model that assumed complete gas mixing after puncture, the Uniform Mixing Model, showed significantly better agreement with the data than the model that assumed no change in the composition of the inner container, referred to as the Non-Uniform Mixing Model. Both models were implemented as Microsoft{reg_sign} Excel spreadsheet calculations, which utilize macros, to include the effects of uncertainties and biases in the measurements of process parameters and in the models. Potential inleakage of gas from the glovebox is also addressed. The spreadsheet utilizing the Uniform Mixing Model, which was validated by data from the characterization tests, is used to evaluate the pre-puncture composition and pressure within the inner 3013 container. This spreadsheet model is called the Gas Evaluation Software Tool (GEST).
Date: April 1, 2008
Creator: Hardy, B; Stephen Harris, S; Matthew Arnold, M & Steve Hensel, S
Partner: UNT Libraries Government Documents Department

Reduction of Data for Piston Gage Pressure Measurements

Description: Report issued by the U.S. National Bureau of Standards discussing piston gage pressure and reducing errors of measurement. Sources of error are described and evaluated in order to "reduce the magnitude of overall error of measurement" (p. 1). This report includes tables, and illustrations.
Date: June 17, 1963
Creator: Cross, J. L.
Partner: UNT Libraries Government Documents Department

Laser barometer

Description: This paper describes an invention of a pressure measuring instrument which uses laser radiation to sense the pressure in an enclosed environment by means of measuring the change in refractive index of a gas - which is pressure dependent.
Date: April 1, 1998
Creator: Abercrombie, K.R.; Shiels, D. & Rash, T.
Partner: UNT Libraries Government Documents Department

Detonation electric effect and composite explosives. Quarterly report, October--December 1971

Description: Materials were obtained to allow formulation of a heavy-metal loaded HE similar to one which displayed strange behavior in previous detonation electric effect studies. A series of C-J pressure tests will be conducted on LX-09-0 as part of a parameter study and familiarization series. RX-25-AA samples are being prepared for testing at the present time.
Date: September 1, 1997
Creator: Kramer, P.E.
Partner: UNT Libraries Government Documents Department

Particle Pressures in Fluidized Beds. Final report

Description: This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction): they impart to the bed. So rather than directly measure the particle pressure, we inferred the values of the elasticity from measurements of instability growth in liquid beds the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined)and then working backwards to determine the unknown coefficients, including the elasticity.
Date: September 1, 1996
Creator: Campbell, C.S.; Rahman, K. & Jin, C.
Partner: UNT Libraries Government Documents Department

Ribbon Surface Pressure and Wake Velocity Data for the Experimental Validation of a Vortex-Based Parachute Inflation Code

Description: An experiment to measure surface pressure data on a series of three stainless steel simulated parachute ribbons was conducted. During the first phase of the test, unsteady pressure measurements were made on the windward and leeward sides of the ribbons to determine the statistical properties of the surface pressures. Particle Image Velocimetry (PIV) measurements were simultaneously made to establish the velocity field in the wake of the ribbons and its correlation with the pressure measurements. In the second phase of the test, steady-state pressure measurements were made to establish the pressure distributions. In the third phase, the stainless steel ribbons were replaced with nylon ribbons and PIV measurements were made in the wake. A detailed error analysis indicates that the accuracy of the pressure measurements was very good. However, an anomaly in the flow field caused the wake behind the stainless steel ribbons to establish itself in a stable manner on one side of the model. This same stability was not present for the nylon ribbon model although an average of the wake velocity data indicated an apparent 2{degree} upwash in the wind tunnel flow field. Since flow angularity upstream of the model was not measured, the use of the data for code validation is not recommended without a second experiment to establish that upstream boundary condition.
Date: June 1, 2001
Partner: UNT Libraries Government Documents Department

Detailed Chemical Kinetic Mechanisms for Combustion of Oxygenated Fuels

Description: Thermodynamic properties and detailed chemical kinetic models have been developed for the combustion of two oxygenates: methyl butanoate, a model compound for biodiesel fuels, and methyl formate, a related simpler molecule. Bond additivity methods and rules for estimating kinetic parameters were adopted from hydrocarbon combustion and extended. The resulting mechanisms have been tested against the limited combustion data available in the literature, which was obtained at low temperature, subatmospheric conditions in closed vessels, using pressure measurements as the main diagnostic. Some qualitative agreement was obtained, but the experimental data consistently indicated lower overall reactivities than the model, differing by factors of 10 to 50. This discrepancy, which occurs for species with well-established kinetic mechanisms as well as for methyl esters, is tentatively ascribed to the presence of wall reactions in the experiments. The model predicts a region of weak or negative dependence of overall reaction rate on temperature for each methyl ester. Examination of the reaction fluxes provides an explanation of this behavior, involving a temperature-dependent competition between chain-propagating unimolecular decomposition processes and chain-branching processes, similar to that accepted for hydrocarbons. There is an urgent need to obtain more complete experimental data under well-characterized conditions for thorough testing of the model.
Date: January 11, 2000
Creator: Fisher, E.M.; Pitz, W.J.; Curran, H.J. & Westbrook, C.K.
Partner: UNT Libraries Government Documents Department

Final report on Task 55

Description: This report very briefly summarizes subcontractor activities related to fiber optic imaging and measurement techniques. Activities described include interferometry measurements of plasma jets and pressure measurement in a shock front. Work on the Russian infrared imaging camera is discussed in somewhat more detail. No work was performed on the mode locked laser.
Date: September 29, 1997
Creator: Forman, P.R.
Partner: UNT Libraries Government Documents Department

Fractured petroleum reservoirs

Description: Total compressibility in a fractured reservoir is estimated using the pressure response due to gravitational potential variations. Both the moon and the sun gravitational potentials are accounted for using the full expression by inclusion of longer-period components. The semi-diurnal and diurnal pressure data show substantial long-term variations. The gravitational potential also contains the same variation trend; the ratio between the potential and pressure has a fairly uniform value over successive cycles. The computed total compressibility is also fairly constant and independent of the cycle. Results show the effects of the time interval over which the pressure measurements are performed as well as the location.
Date: January 10, 2000
Creator: Firoozabadi, A.; Chang, E. & Tang, G.Q.
Partner: UNT Libraries Government Documents Department

FY99 Status Report on the HSV

Description: 'The HSV in storage in MTF has been monitored during FY99, and its overpressure has been sampled and analyzed. The HSV''s internal pressure continues to rise slowly, and the overpressure still analyzes as 100 percent 3He. The titanium tritide sample that was to be monitored annually and which had developed a leak last year has been repaired and isotherms measured. Unfortunately the sample was showing significant unexpected 3He release, so the isotherm data is corrupted by unknown levels of 3He. This release has disqualified this sample for future use, as it is now seriously divergent from the HSV material. A different sample must be selected for subsequent studies.The unexpected 3He releases of the Ti-3 sample and the possible release in other Ti samples have raised a serious issue. It should be determined why this release is occurring, so that an unexpected release of 3He during HSV unloading can be assessed as unlikely.'
Date: October 15, 1999
Creator: Shanahan, K. L.
Partner: UNT Libraries Government Documents Department

Imaging of Acoustically Coupled Oscillations Due to Flow Past a Shallow Cavity: Effect of Cavity Length Scale

Description: Flow-acoustic interactions due to fully turbulent inflow past a shallow axisymmetric cavity mounted in a pipe, which give rise to flow tones, are investigated using a technique of high-image-density particle image velocimetry in conjunction with unsteady pressure measurements. This imaging leads to patterns of velocity, vorticity, streamline topology, and hydrodynamic contributions to the acoustic power integral. Global instantaneous images, as well as time-averaged images, are evaluated to provide insight into the flow physics during tone generation. Emphasis is on the manner in which the streamwise length scale of the cavity alters the major features of the flow structure. These image-based approaches allow identification of regions of the unsteady shear layer that contribute to the instantaneous hydrodynamic component of the acoustic power, which is necessary to maintain a flow tone. In addition, combined image analysis and pressure measurements allow categorization of the instantaneous flow patterns that are associated with types of time traces and spectra of the fluctuating pressure. In contrast to consideration based solely on pressure spectra, it is demonstrated that locked-on tones may actually exhibit intermittent, non-phase-locked images, apparently due to low damping of the acoustic resonator. Locked-on flow tones (without modulation or intermittency), locked-on flow tones with modulation, and non-locked-on oscillations with short-term, highly coherent fluctuations are defined and represented by selected cases. Depending on which of these regimes occur, the time-averaged Q (quality)-factor and the dimensionless peak pressure are substantially altered.
Date: May 24, 2004
Creator: Oshkai, P; Geveci, M; Rockwell, D & Pollack, M
Partner: UNT Libraries Government Documents Department

Vacuum simulation of RF cavities to optimize pump configurations

Description: The pressure history in the components of an rf linac has been modeled using Mathematica.[1] Specifically the Cavity Coupled Drift Tube Linac (CCDTL) and Cavity Coupled Linac (CCL) sections of the Accelerator Production of Tritium (APT) plant [2] have been modeled in order to predict the optimal pump configuration over the 224 meter length. The pressure history in up to 43 sub-volumes within three representative modules (about three meters long) is analyzed in detail. Included in our model are time-dependent outgassing rates and pressure-dependent pump speeds. With this information, we solve for the pressure history during roughing and with turbo and ion pumps. The number and size of each pump is optimized to achieve the desired pressure with minimal costs.
Date: March 1, 1999
Creator: Shen, S & Tung, L S
Partner: UNT Libraries Government Documents Department

Oscillations of a Turbulent Jet Incident Upon an Edge

Description: For the case of a jet originating from a fully turbulent channel flow and impinging upon a sharp edge, the possible onset and nature of coherent oscillations has remained unexplored. In this investigation, high-image-density particle image velocimetry and surface pressure measurements are employed to determine the instantaneous, whole-field characteristics of the turbulent jet-edge interaction in relation to the loading of the edge. It is demonstrated that even in absence of acoustic resonant or fluid-elastic effects, highly coherent, self-sustained oscillations rapidly emerge above the turbulent background. Two clearly identifiable modes of instability are evident. These modes involve large-scale vortices that are phase-locked to the gross undulations of the jet and its interaction with the edge, and small-scale vortices, which are not phase-locked. Time-resolved imaging of instantaneous vorticity and velocity reveals the form, orientation, and strength of the large-scale concentrations of vorticity approaching the edge in relation to rapid agglomeration of small-scale vorticity concentrations. Such vorticity field-edge interactions exhibit rich complexity, relative to the simplified pattern of vortex-edge interaction traditionally employed for the quasi-laminar edgetone. Furthermore, these interactions yield highly nonlinear surface pressure signatures. The origin of this nonlinearity, involving coexistence of multiple frequency components, is interpreted in terms of large- and small-scale vortices embedded in distributed vorticity layers at the edge. Eruption of the surface boundary layer on the edge due to passage of the large-scale vortex does not occur; rather apparent secondary vorticity concentrations are simply due to distension of the oppositely-signed vorticity layer at the tip of the edge. The ensemble-averaged turbulent statistics of the jet quickly take on an identity that is distinct from the statistics of the turbulent boundary layer in the channel. Large increases in Reynolds stress occur due to onset of the small-scale concentrations of vorticity immediately downstream of separation; substantial increases at locations further ...
Date: September 19, 2000
Creator: Lin, J.C. & Rockwell, D.
Partner: UNT Libraries Government Documents Department