Differential Pressure Transmitters, Span-Shift Errors With Static Pressure

1972 ◽  
Vol 94 (4) ◽  
pp. 893-896 ◽  
Author(s):  
L. T. Akeley
Keyword(s):  
High Pressure ◽  
Static Pressure ◽  
Test Methods ◽  
Differential Pressure ◽  
Shift Performance ◽  
Mercury Manometer

The author reviews methods of calibrating low-differential (25–300 in. H2O) D.P. transmitters at high (up to 3000 psig) static pressure. Various test methods are described along with discussion of their merits. Included are use of one or more deadweight testers (gas or liquid) and use of a high-pressure mercury manometer as a standard. Five D.P. transmitters of different construction are tested and their static span-shift performance reported.

Influence of Turbulent Flow Characteristics and Coherent Vortices on the Pressure Recovery of Annular Diffusers: Part A — Experimental Results

2015 ◽  
Author(s):  
Marcus Kuschel ◽  
Bastian Drechsel ◽  
David Kluß ◽  
Joerg R. Seume
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Static Pressure ◽  
Turbulent Transport ◽  
Axial Flow ◽  
Pressure Recovery ◽  
Turbulence Structure ◽  
Reynolds Stresses ◽  
Wide Range ◽  
Operating Points

Exhaust diffusers downstream of turbines are used to transform the kinetic energy of the flow into static pressure. The static pressure at the turbine outlet is thus decreased by the diffuser, which in turn increases the technical work as well as the efficiency of the turbine significantly. Consequently, diffuser designs aim to achieve high pressure recovery at a wide range of operating points. Current diffuser design is based on conservative design charts, developed for laminar, uniform, axial flow. However, several previous investigations have shown that the aerodynamic loading and the pressure recovery of diffusers can be increased significantly if the turbine outflow is taken into consideration. Although it is known that the turbine outflow can reduce boundary layer separations in the diffuser, less information is available regarding the physical mechanisms that are responsible for the stabilization of the diffuser flow. An analysis using the Lumley invariance charts shows that high pressure recovery is only achieved for those operating points in which the near-shroud turbulence structure is axi-symmetric with a major radial turbulent transport component. This turbulent transport originates mainly from the wake and the tip vortices of the upstream rotor. These structures energize the boundary layer and thus suppress separation. A logarithmic function is shown that correlates empirically the pressure recovery vs. the relevant Reynolds stresses. The present results suggest that an improved prediction of diffuser performance requires modeling approaches that account for the anisotropy of turbulence.

Development of a Lifetime Pressure Sensitive Paint Procedure for High-Pressure Vane Testing

2021 ◽  
Author(s):  
Papa Aye N. Aye-Addo ◽  
Guillermo Paniagua ◽  
David G. Cuadrado ◽  
Lakshya Bhatnagar ◽  
Antonio Castillo Sauca ◽  
...  
Keyword(s):  
High Pressure ◽  
Test Section ◽  
Static Pressure ◽  
Pressure Field ◽  
Optical Measurements ◽  
Wall Region ◽  
Pressure Amplitude ◽  
Pressure Sensitive Paint ◽  
Suction Surface ◽  
Pressure Sensitive

Abstract Optical measurements based on fast response Pressure Sensitive Paint (PSP) provide enhanced spatial resolution of the pressure field. This paper presents laser lifetime PSP at 20 kHz, with precise calibrations, and results from a demonstration in an annular vane cascade. The laser lifetime PSP methodology is first evaluated in a linear wind tunnel with a converging-diverging nozzle followed by a wavy surface. This test section is fully optically accessible with maximum modularity. A data reduction procedure is proposed for the PSP calibration, and optimal pixel binning is selected to reduce the uncertainty. In the annular test section, laser lifetime PSP was used to measure the time-averaged static pressure field on a section of the suction surface of a high-pressure turbine vane. Tests were performed at engine representative conditions in the Purdue Big Rig for Annular Stationary Turbine Analysis module at the Purdue Experimental Turbine Aerothermal Lab. The 2-D pressure results showed a gradual increase of pressure in the spanwise and flow directions, corroborated with local static pressure taps and computational results. The variation in PSP thickness was measured as a contribution to the uncertainty. The discrete Fourier transform of the unsteady pressure signal showed increased frequency content in wind-on conditions compared to wind-off conditions at the mid-span and 30% span. Compared to the mid-span region, the hub end wall region had an increase in frequencies and pressure amplitude. This result was anticipated given the expected presence of secondary flow structures in the near hub region.

scholarly journals Application of Comprehensive Rectification Method in Rectification of Buildings

2020 ◽  
Vol 165 ◽  
pp. 04004
Author(s):  
Xiaoyi Yang
Keyword(s):  
High Pressure ◽  
Static Pressure ◽  
Foundation Settlement ◽  
Simultaneous Application ◽  
Irrigation Method ◽  
Loading Method ◽  
Forced Landing

This year, there are two ways to rectify buildings: forced landing and jacking up. The method of landing is to increase the settlement of the smaller side of the building, and the method of landing is the digging soil method, the irrigation method, the pile loading method, etc. the jacking method is on the basis of the stable foundation settlement, and the upper structure or foundation is raised on the larger side of the building so that the building will be leveled back, and the jacking method has static pressure pile top. Lifting method, lime pile lifting method, high pressure jet pile jacking method, etc. But in practice, a kind of rectification method cannot meet the purpose of building rectification. It needs two or more rectification methods to achieve the goal. This method of simultaneous application of two or more rectification methods on the same building is called the comprehensive rectification method. In this paper, some common rectifying methods are introduced. At the same time, the application of the comprehensive rectification method in engineering is explained in the background of practical engineerings.

High pressure Water Gas Shift performance over a commercial non-sulfide CoMo catalyst using industrial coal-derived syngas

Fuel ◽  
2012 ◽  
Vol 97 ◽  
pp. 428-434 ◽  
Author(s):  
A.R. de la Osa ◽  
A. De Lucas ◽  
A. Romero ◽  
P. Casero ◽  
J.L. Valverde ◽  
...  
Keyword(s):  
High Pressure ◽  
Water Gas Shift ◽  
Shift Performance ◽  
Pressure Water ◽  
Como Catalyst ◽  
Water Gas

Investigation of Self-Recycling-Casing-Treatment (SRCT) Influence on Stability of High Pressure Ratio Centrifugal Compressor With a Volute

2011 ◽  
Author(s):  
Mingyang Yang ◽  
Ricardo Martinez-Botas ◽  
Yangjun Zhang ◽  
Xinqian Zheng ◽  
Takahiro Bamba ◽  
...  
Keyword(s):  
High Pressure ◽  
Numerical Method ◽  
Flow Rate ◽  
Centrifugal Compressor ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Flow Distortion ◽  
Casing Treatment ◽  
High Pressure Ratio ◽  
The Stability

Large feasible operation range is a challenge for high pressure ratio centrifugal compressor of turbocharger in vehicle engine. Self-Recycling-Casing-Treatment (SRCT) is a widely used flow control method to enlarge the range for this kind of compressor. This paper investigates the influence of symmetrical/asymmetrical SRCT (ASRCT) on the stability of a high pressure ratio centrifugal compressor by experimental testing and numerical simulation. Firstly, the performance of the compressor with/without SRCT is tested is measured investigate the influence of flow distortion on the stability of compressor as well as the numerical method validation. Then detailed flow field investigation is conducted by experimental measurement and the numerical method to unveil the reasons for stability enhancement by symmetrical/asymmetrical SRCT. Results show that static pressure distortion at impeller outlet caused by the volute can make passages be confronted with flow distortion less stable than others because of their larger positive slope of T-S pressure ratio performance at small flow rate. SRCT can depress the flow distortion and reduce the slope by non-uniform recycling flow rate at impeller inlet. Moreover, ASRCT can redistribute the recycling flow in circumferential direction according to the asymmetric geometries. When the largest recycling flow rate is imposed on the passage near the distorted static pressure, the slope will be the most effectively reduced. Therefore, the stability is effectively enhanced by the optimized recycling flow device.

Time-Averaged and Time-Accurate Aerodynamic Effects of Rotor Purge Flow for a Modern, One and One-Half Stage High-Pressure Turbine—Part II: Analytical Flow Field Analysis

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Brian R. Green ◽  
Randall M. Mathison ◽  
Michael G. Dunn
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Film Cooling ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Field Analysis ◽  
High Pressure Turbine ◽  
Purge Flow

The detailed mechanisms of purge flow interaction with the hot-gas flow path were investigated using both unsteady computationally fluid dynamics (CFD) and measurements for a turbine operating at design corrected conditions. This turbine consisted of a single-stage high-pressure turbine and the downstream, low-pressure turbine nozzle row with an aerodynamic design equivalent to actual engine hardware and typical of a commercial, high-pressure ratio, transonic turbine. The high-pressure vane airfoils and inner and outer end walls incorporated state-of-the-art film cooling, and purge flow was introduced into the cavity located between the high-pressure vane and disk. The flow field above and below the blade angel wing was characterized by both temperature and pressure measurements. Predictions of the time-dependent flow field were obtained using a three-dimensional, Reynolds-averaged Navier–Stokes CFD code and a computational model incorporating the three blade rows and the purge flow cavity. The predictions were performed to evaluate the accuracy obtained by a design style application of the code, and no adjustment of boundary conditions was made to better match the experimental data. Part I of this paper compared the predictions to the measurements in and around the purge flow cavity and demonstrated good correlation. Part II of this paper concentrates on the analytical results, looking at the primary gas path ingestion mechanism into the cavity as well as the effects of the rotor purge on the upstream vane and downstream rotor aerodynamics and thermodynamics. Ingestion into the cavity is driven by high static pressure regions downstream of the vane, high-velocity flow coming off the pressure side of the vane, and the blade bow waves. The introduction of the purge flow is seen to have an effect on the static pressure of the vane trailing edge in the lower 5% of span. In addition, the purge flow is weak enough that upon exiting the cavity, it is swept into the mainstream flow and provides no additional cooling benefits on the platform of the rotating blade.

Experimental Investigation of Static Pressure Characteristics of FBG Differential Pressure Flow Sensor

2013 ◽  
Vol 336-338 ◽  
pp. 134-138 ◽  
Author(s):  
Chun Tong Liu ◽  
Zhen Xin He ◽  
Yang Zhang ◽  
Hong Cai Li
Keyword(s):  
Static Pressure ◽  
Sensitivity Coefficient ◽  
Differential Pressure ◽  
Flow Sensor ◽  
Experimental Result ◽  
Hydraulic Pressure ◽  
Hysteresis Phenomenon ◽  
Pressure Flow ◽  
Pressure Calibrator ◽  
Pressure Characteristics

On the basis of FBG (Fiber Bragg Grating) sensor principle analysis, a differential pressure flow sensor using FBG has been designed. The static pressure characteristics of the sensor were experimental studied by the hydraulic pressure calibrator and Q8384 spectrometer, and the experimental result errors were analyzed. Experimental results show that, the sensitivity coefficient of FBG is 3 pm/KPa in the differential pressure range of 0~0.35 MPa. The changes of Bragg wavelength with the pressure changes showing a good linear relationship and repetitive, and the hysteresis phenomenon is minor, which can be used for flow measurement of hydraulic system in special areas.

Pressure Measurements Around a Rotating Cylinder With and Without Crossflow

1993 ◽  
Vol 115 (3) ◽  
pp. 526-528 ◽  
Author(s):  
A. A. Tawfek ◽  
B. V. S. S. S. Prasad ◽  
A. K. Mohanty
Keyword(s):  
Pressure Transducer ◽  
Static Pressure ◽  
Rotating Cylinder ◽  
Differential Pressure ◽  
Pressure Measurements ◽  
Orthogonal Axis ◽  
Differential Pressure Transducer ◽  
Slip Ring

Static pressure measurements around a cylinder rotating about an orthogonal axis with and without superimposed crossflow are carried out by using a capacitance type differential pressure transducer in conjunction with a slip-ring apparatus. A coefficient of pressure (Cp) is defined for the rotating cylinder and typical variations of Cp along its length and periphery are presented.

The Formation of Coesite under Minimum Static Pressure

2014 ◽  
Vol 675-677 ◽  
pp. 38-41
Author(s):  
De Jun Wang ◽  
Run Ru Liu ◽  
Leng Jing
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Mechanical Milling ◽  
Static Pressure ◽  
High Energy ◽  
Initial Material ◽  
The Earth

Using the α-SiO2 and conducted by high-energy mechanical milling as the initial material, we investigated the synthesis of coesite under high temperature and high pressure in the condition of adding a certain amount of hard Fe fillings. The synthetic samples are measured by XRD and Raman, and the results show that a small amount of small-sized coesite can be obtained under 2.5 GPa. Based on these results, it is considered that the forming depth of natural coesite under the earth is likely to be obviously shallower than that of plate exhumation in the traditional subduction-exhumation hypothesis.

Theory and Application of Axisymmetric Endwall Contouring for Compressors

2011 ◽  
Author(s):  
Georg Kro¨ger ◽  
Christian Voß ◽  
Eberhard Nicke ◽  
Christian Cornelius
Keyword(s):  
High Pressure ◽  
Pressure Gradient ◽  
Gas Turbine ◽  
Static Pressure ◽  
Aerodynamic Performance ◽  
Leakage Flow ◽  
High Pressure Compressor ◽  
Blade Tip ◽  
Stage Efficiency ◽  
Pressure Compressor

Engine operating range and efficiency are of increasing importance in modern compressor design for heavy duty gas turbines and aircraft engines. These highly challenging objectives can only be met if all components provide high aerodynamic performance and stability. The aerodynamic losses of highly loaded axial compressors are mainly influenced by the leakage flow through clearance gaps. Especially the leakage flow due to the radial clearances of rotor blades affects negatively both, the efficiency and the operating range of the engine. Recent publications showed that the clearance flow and the clearance vortex can be influenced by an additional static pressure gradient at the outer casing, which is created by an axisymmetric wavy casing shape. A notable performance increase of up to 0.4% stage efficiency at design point conditions was reported for high pressure stages with large tip clearance heights [1] as well as for a transonic stage with a relatively small radial clearance gap [2]. An analytic approach to predict the effects of axisymmetric casing contouring has been developed at DLR, Institute of Propulsion Technology, and is outlined in the first part of this work. The characteristic behavior of the clearance vortex in an adverse pressure gradient is discussed by means of an inviscid vortex model [3]. The critical vortex parameters are isolated and related to the static pressure increase due to the casing contour. The second part illustrates the application of an axisymmetric endwall contour. A three dimensional optimization of the outer casing and the corresponding blade tip airfoil section of a typical gas turbine high pressure compressor stage with a high number of free variables is presented. The optimization led to a significant increase in aerodynamic performance of about 0.8% stage efficiency and to a notable reduction of the endwall blockage at ADP conditions. Furthermore, an improved off-design performance was found and a simple design rule is given to transfer both, the casing contour and the blade tip section modification on similar high pressure compressor blades. Based on these design rules the results of the optimized stages were applied to the rear stages of a Siemens gas turbine compressor CFD model. An increase of 0.3% full compressor performance was reached at design point conditions.

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