Experimental investigations of direct measurement of borehole wall pressure under decoupling charge

2022 ◽  
Vol 120 ◽  
pp. 104280
Author(s):  
Xin'ao Wei ◽  
Qiyue Li ◽  
Chunde Ma ◽  
Longjun Dong ◽  
Jing Zheng ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Wall Pressure ◽  
Borehole Wall ◽  
Experimental Investigations

scholarly journals Experimental Investigations of a Recently Developed Supersonic Compressor Stage (Rotor and Stage Performance)

1974 ◽  
Author(s):  
H. Simon ◽  
D. Bohn
Keyword(s):  
Static Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Strong Shock ◽  
Wall Pressure ◽  
Experimental Investigations ◽  
Pressure Measurements ◽  
Compressor Stage ◽  
Pressure Transducers ◽  
Rotor Type

The experimental investigations of a recently developed supersonic compressor stage working with a strong shock wave both in the rotor and stator are described. The shock in the inlet area of the rotor is stabilized by the geometry of the rotor blade channel, whereas the position of shocks in the stator is controlled by the back pressure. Due to this, the static pressure rise is distributed to the rotor and stator avoiding a higher loading of the stator. In the first part the performance of the rotor alone has been investigated. The conducted probe and static wall pressure measurements allowed a detailed analysis of the flow through the rotor. The determined performance characteristics of the rotor show the peculiarities of the rotor at different speeds and throttle positions. In addition to the static wall pressure measurements the nonsteady pressure distributions have been measured at the casing wall by piezoelectric pressure transducers. Since this rotor (type ②) has been designed with the same relative inlet Mach number and turning as the previously investigated supersonic rotor (type ①), a direct comparison of these rotors can be made. In the second part of these investigations the rotor of type ② has been combined with a tandem cascade as a stator, to investigate the supersonic compressor stage. With heavy throttling a static pressure ratio of 3,5 (p3/p1) has been achieved. The evaluation of the probe measurements allowed a better estimation of the overall performance of this supersonic compressor stage.

scholarly journals Experiment on of Nozzle Flow with Sudden Expansion at Mach 1.1

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1769-1775 ◽  
Keyword(s):  
Mach Number ◽  
Control Mechanism ◽  
Separated Flow ◽  
Flow Region ◽  
Wall Pressure ◽  
Base Pressure ◽  
Sudden Expansion ◽  
Experimental Investigations ◽  
Pressure Regulator ◽  
The Impact

This present study discusses the outcome of the experimental investigations, and the efficacy of the tiny jets used to regulate the base pressure as well as the wall pressure in suddenly expanded flow. The control mechanism as tiny jets having a cross-section of 1 mm diameter was employed as the base pressure regulator at the exit periphery of the nozzle. The experiments were carried out to investigate and record the flow field at the rear end of the separated flow region for area ratio 4.84. Four tiny jets were placed at a distance of 6.5 mm away from the primary jet coming from the nozzle exit at ninety degrees apart, and the tiny control jets were flowing at sonic Mach number. The actual Mach number of the main jet was 1.1. The experimentation was accomplished at a different level of expansion (i. e., NPR = 3, 5, 7, 9, and 11) and the L/D ratio considered was from 10 to 1. This study mainly focuses on the development of the flow in the suddenly expanded duct, nature of the flow in the duct, and the impact of the Control on the wall pressure and the magnitude of the pressure along the duct. The wall pressure in the smooth duct is not unfavorably influenced by the control jets.

Experimental Investigations on the Thermal Conductivity of Silica Aerogels by a Guarded Thin-Film-Heater Method

2009 ◽  
Vol 131 (7) ◽  
Author(s):  
Sandra Spagnol ◽  
Bérangère Lartigue ◽  
Alain Trombe ◽  
Florence Despetis
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Thermal Conductivity ◽  
Direct Measurement ◽  
Silica Aerogels ◽  
Experimental Investigations ◽  
Experimental Setup ◽  
Insulating Materials ◽  
Grain Sizes ◽  
Major Interest

A thin-film-heater method is setup to measure the thermal conductivity of super insulating materials such as silica aerogels. The experimental setup is purposely designed for insulating materials and allows direct measurement of the thermal conductivity. Few experimental data are available in the literature concerning thermal conductivity of aerogels even though these materials are of major interest in thermal insulation. More data are necessary in order to understand thermal transport and to validate existing models. Monolithic and granular silica aerogels are investigated. Our experimental technique enables to quantify the influence of important parameters, such as air pressure and distribution of grain sizes, on the insulating performance of this material.

Numerical Calculation of Wall Pressure Fluctuations in a Centrifugal Fan

2004 ◽  
Author(s):  
Sandra Velarde-Sua´rez ◽  
Rafael Ballesteros-Tajadura ◽  
Juan Pablo Hurtado-Cruz ◽  
Carlos Santolaria-Morros
Keyword(s):  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Power Spectra ◽  
Wall Pressure ◽  
Operating Conditions ◽  
Numerical Code ◽  
Experimental Investigations ◽  
Centrifugal Fan ◽  
Wall Pressure Fluctuations ◽  
Flow Phenomena

In this work, a numerical code has been applied in order to obtain the wall pressure fluctuations at the volute of an industrial centrifugal fan. The numerical results have been contrasted using previous experimental investigations carried out in the same machine. A three-dimensional numerical simulation of the complete unsteady flow on the whole impeller-volute configuration has been carried out using the computational fluid dynamics code FLUENT®. This code has been employed to calculate the time-dependent pressure both in the impeller and in the volute. In this way, the pressure fluctuations in some locations over the volute wall have been obtained. The power spectra of these fluctuations have been calculated, showing an important peak at the blade passing frequency. The amplitude of this peak presents the highest values near the volute tongue, but the spatial pattern over the volute extension is different depending on the operating conditions. The code has successfully simulated the volute pressure fluctuations due to the aerodynamic field, capturing the main flow phenomena such as the jet-wake effects and the impeller-volute interaction.

A Comparison of Turbulent Boundary Layer Wall-Pressure Spectra

1992 ◽  
Vol 114 (3) ◽  
pp. 338-347 ◽  
Author(s):  
W. L. Keith ◽  
D. A. Hurdis ◽  
B. M. Abraham
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Reynolds Number ◽  
Turbulent Boundary Layer ◽  
Scaling Laws ◽  
Wall Pressure ◽  
Experimental Investigations ◽  
Length Scale ◽  
Momentum Thickness ◽  
Insight Into

Turbulent boundary layer wall-pressure spectra from various experimental investigations and a recent numerical simulation are presented. The spectra are compared in nondimensional form with three commonly used scaling laws. Attenuations resulting from inadequate sensor spatial resolution are shown to be of primary importance at the higher frequencies. The dependence of the scaling laws on momentum thickness Reynolds number is discussed. The ratio of the outer to the inner boundary layer length scale is shown to provide insight into the observed trends in the spectra.

Direct Measurement of the Listening of Hearing-Impaired Children

1970 ◽  
Vol 13 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Mary Mira
Keyword(s):  
Direct Measurement ◽  
Continuous Measurement ◽  
Hearing Impaired ◽  
Reinforcement System ◽  
School Aged Children ◽  
Conjugate Reinforcement ◽  
Impaired Children ◽  
Hearing Impaired Children

Listening, a significant dimension of the behavior of hearing-impaired children, may be measured directly by recording childrens' responses to obtain audio narrations programmed via a conjugate reinforcement system. Twelve hearing-impaired, school-aged children responded in varying ways to the opportunity to listen. Direct and continuous measurement of listening has relevance for evaluation of remediation methods and for discovery of variables potentially related to listening.

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