scholarly journals Experimental and Numerical Study on Pressure Distribution of 90° Elbow for Flow Measurement

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Beibei Feng ◽  
Shiming Wang ◽  
Shengqiang Li ◽  
Xingtuan Yang ◽  
Shengyao Jiang
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Pressure Distribution ◽  
Flow Measurement ◽  
Static Pressure ◽  
Numerical Study ◽  
Numerical Approach ◽  
Test System ◽  
Numerical Results ◽  
Helium Gas

Numerical simulation is performed to investigate the pressure distribution of helium gas under high pressure and high temperature for 10 MW High Temperature Gas-Cooled Reactor (HTGR-10). Experimental studies are first conducted on a self-built test system to investigate the static pressure distribution of a 90° elbow and validate the credibility of the computational approach. The 90° elbow is designed and manufactured geometrically the same as HTGR-10. Based on the experimental data, comparison of static pressure of inner wall and outer wall of 90° elbow with numerical results is carried out to verify the numerical approach. With high agreement between experimental results and numerical results of water flowing through 90° elbow, flow characteristics of helium gas under high pressure and high temperature are investigated on the confirmed numerical approach for flow measurement. And wall pressure distribution of eight cross sections of 90° elbow is given in detail to represent the entire region of the elbow.

Numerical Study of Bicomponent Droplet Vaporization in a High Pressure Environment

1996 ◽  
Author(s):  
J. Stengele ◽  
H.-J. Bauer ◽  
S. Wittig
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Phase ◽  
Numerical Study ◽  
Droplet Evaporation ◽  
Single Component ◽  
Vapor Concentration ◽  
Diffusion Limit ◽  
Evaporation Process ◽  
Droplet Vaporization

The understanding of multicomponent droplet evaporation in a high pressure and high temperature gas is of great importance for the design of modern gas turbine combustors, since the different volatilities of the droplet components affect strongly the vapor concentration and, therefore, the ignition and combustion process in the gas phase. Plenty of experimental and numerical research is already done to understand the droplet evaporation process. Until now, most numerical studies were carried out for single component droplets, but there is still lack of knowledge concerning evaporation of multicomponent droplets under supercritical pressures. In the study presented, the Diffusion Limit Model is applied to predict bicomponent droplet vaporization. The calculations are carried out for a stagnant droplet consisting of heptane and dodecane evaporating in a stagnant high pressure and high temperature nitrogen environment. Different temperature and pressure levels are analyzed in order to characterize their influence on the vaporization behavior. The model employed is fully transient in the liquid and the gas phase. It accounts for real gas effects, ambient gas solubility in the liquid phase, high pressure phase equilibrium and variable properties in the droplet and surrounding gas. It is found that for high gas temperatures (T = 2000 K) the evaporation time of the bicomponent droplet decreases with higher pressures, whereas for moderate gas temperatures (T = 800 K) the lifetime of the droplet first increases and then decreases when elevating the pressure. This is comparable to numerical results conducted with single component droplets. Generally, the droplet temperature increases with higher pressures reaching finally the critical mixture temperature of the fuel components. The numerical study shows also that the same tendencies of vapor concentration at the droplet surface and vapor mass flow are observed for different pressures. Additionally, there is almost no influence of the ambient pressure on fuel composition inside the droplet during the evaporation process.

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.

Investigating the Cause of Computational Fluid Dynamics Deficiencies in Accurately Predicting the Efficiency and Performance of High Pressure Turbines: A Combined Experimental and Numerical Study

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Meinhard T. Schobeiri ◽  
S. Abdelfattah ◽  
H. Chibli
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Numerical Study ◽  
Turbine Rotor ◽  
Sensitivity Study ◽  
Numerical Results ◽  
Performance Measurements ◽  
And Performance ◽  
The Individual

Despite the tremendous progress over the past three decades in the area of turbomachinery computational fluid dynamics, there are still substantial differences between the experimental and the numerical results pertaining to the individual flow quantities. These differences are integrally noticeable in terms of major discrepancies in aerodynamic losses, efficiency, and performance of the turbomachines. As a consequence, engine manufacturers are compelled to frequently calibrate their simulation package by performing a series of experiments before issuing efficiency and performance guaranty. This paper aims at identifying the quantities, whose simulation inaccuracies are preeminently responsible for the aforementioned differences. This task requires (a) a meticulous experimental investigation of all individual thermofluid quantities and their interactions, resulting in an integral behavior of the turbomachine in terms of efficiency and performance; (b) a detailed numerical investigation using appropriate grid densities based on simulation sensitivity; and (c) steady and transient simulations to ensure their impact on the final numerical results. To perform the above experimental and numerical tasks, a two-stage, high-pressure axial turbine rotor has been designed and inserted into the TPFL turbine research facility for generating benchmark data to compare with the numerical results. Detailed interstage radial and circumferential traversing presents a complete flow picture of the second stage. Performance measurements were carried out for design and off-design rotational speed. For comparison with numerical simulations, the turbine was numerically modeled using a commercial code. An extensive mesh sensitivity study was performed to achieve a grid-independent accuracy for both steady and transient analysis.

Application of Nonlinear Elastic Wave Spectroscopy in the Field of Nuclear Energy

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
J. Patera ◽  
J. Jansa
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Elastic Wave ◽  
Power Plants ◽  
Nuclear Energy ◽  
Test System ◽  
Test Method ◽  
Nonlinear Elastic ◽  
Nonlinear Elastic Wave ◽  
High Temperature High Pressure

Abstract In the field of nuclear energy, two particular applications are considered—the measurement of biological shielding concrete and measurement of high-temperature high-pressure piping. For the measurement of biological shielding concrete, a special manipulator was developed, which is applied through the ionization channels of VVER-440 power plants. Biological shielding concrete is covered on all sides with an 11 mm thick steel liner preventing its assessment using any conventional test method. For the measurement of high-temperature high-pressure piping, acoustic emission sensors installed in the LEMOP system (NPP Temelin) are used for both excitation and data acquisition. In operation, this piping is covered with glass wool insulation, but installed sensors on the waveguides make it possible to assess pipelines without removing the insulation. To demonstrate the material degradation, a set of concrete test specimens and a set of steel test specimens were made. Nonlinear elastic wave spectroscopy is a test method based on measuring the elastic–plastic response of the material whose plastic component is caused by microcracks. Part of this response may be caused by inhomogeneity of the material itself or the nonlinearity of the test system used, which is to be minimized in the measurement. Due to degradation, the number of microcracks increases, increasing the total nonlinear response of the material. The aim of this approach is to monitor the degradation of concrete and metallic materials based on the response of the test system to ultrasonic excitation.

On the Reliability of RANS and URANS Numerical Results for High-Pressure Turbine Simulations: A Benchmark Experimental and Numerical Study on Performance and Interstage Flow Behavior of High-Pressure Turbines at Design and Off-Design Conditions Using Two Different Turbine Designs

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
M. T. Schobeiri ◽  
S. Abdelfattah
Keyword(s):  
High Pressure ◽  
Numerical Study ◽  
Flow Behavior ◽  
Sensitivity Study ◽  
Numerical Results ◽  
Experimental Investigations ◽  
Predictive Capability ◽  
Two Stage ◽  
Flow Through ◽  
And Performance

Improved computational fluid dynamics tools based on Reynolds-averaged Navier–Stokes (RANS) equations have shown that the behavior of simple flow cases can be predicted with a reasonable degree of accuracy. Their predictive capability, however, substantially diminishes whenever major secondary vortices, adverse pressure gradients, and wake-boundary layer interactions are present. Flow through high-pressure (HP) turbine components uniquely incorporates almost all of the above features, interacting with each other and determining the efficiency and performance of the turbine. Thus, the degree of accuracy of predicting the flow through a HP turbine can be viewed as an appropriate benchmark test for evaluating the predictive capability of any RANS-based method. Detailed numerical and experimental investigations of different HP turbines presented in this paper have revealed substantial differences between the experimental and the numerical results pertaining to the individual flow quantities. This paper aims at identifying the quantities whose simulation inaccuracies are pre-eminently responsible for the aforementioned differences. This task requires (a) a meticulous experimental investigation of all individual thermofluid quantities and their interactions resulting in an integral behavior of the turbomachine in terms of efficiency and performance, (b) a detailed numerical investigation using appropriate grid densities based on simulation sensitivity, and (c) steady and transient simulations to ensure their impact on the final numerical results. To perform the above experimental and numerical tasks, two different HP turbines were investigated: (1) a two-stage turbine with moderately compound-leaned stator blades and (2) a three-stage turbine rotor with compound-leaned stator and rotor blades. Both turbines have been thoroughly measured and numerically simulated using RANS and URANS. Detailed interstage radial and circumferential traversing presents a complete flow picture of the second stage. Performance measurements were carried out for design and off-design rotational speeds. For comparison with numerical simulations, the turbines were numerically modeled using a commercially available code. An extensive mesh sensitivity study was performed to achieve a grid-independent accuracy for both steady and transient analysis. Comparison of RANS/URANS results with the experimental ones revealed differences in total pressure for the two-stage turbine of up to 5%. A significantly lower difference of less than 0.2% is observed for the three-stage turbine with specially designed blades to suppress the secondary flow losses. Analyzing the physical background of a RANS-based solver, it was argued that the differences of individual quantities exhibited in the paper were attributed to the deficiencies in dissipation and transition models.

Experimental Research on Proppant Transport Performance of GRF-CO2 Fracturing Fluid

2013 ◽  
Vol 807-809 ◽  
pp. 2583-2588 ◽  
Author(s):  
Xiang Rong Luo ◽  
Shu Zhong Wang ◽  
Xiao Sun ◽  
Xiao Juan Ren
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
High Temperature ◽  
Large Scale ◽  
Settling Velocity ◽  
Test System ◽  
Average Error ◽  
Fracturing Fluid ◽  
Proppant Transport ◽  
Fluid Test

In this article, the experimental study on proppant transport performance of GRF-CO2 system is performed by using the large-scale foam fracturing fluid test system of high temperature and high pressure, and critical settling velocity and proppant settling velocity are obtained.Research results show that the critical settling velocity increases with the temperature rising, in foaming cases,decreases with the foam quality and sand ratio rising.The correlations for GRF-CO2 fracturing final proppant settling velocity within solution and the critical settling velocity have been obtained, all kinds of average error is less than 14%.

The Influence of Roughness on a High-Pressure Steam Turbine Stage: An Experimental and Numerical Study

2014 ◽  
Author(s):  
Juri Bellucci ◽  
Filippo Rubechini ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Numerical Study ◽  
Practical Interest ◽  
Numerical Approach ◽  
Fine Tuning ◽  
High Pressure Steam ◽  
Pressure Steam ◽  
High Pressure Stage ◽  
The Impact

This work deals with the influence of roughness on high-pressure steam turbine stages. It is divided in three parts. In the first one, an experimental campaign on a linear cascade is described, in which blade losses are measured for different values of surface roughness and in a range of Reynolds numbers of practical interest. The second part is devoted to the basic aspects of the numerical approach, and consists of a detailed discussion of the roughness models used for computations. The fidelity of such models is then tested against measurements, thus allowing their fine-tuning and proving their reliability. Finally, comprehensive CFD analysis is carried out on a high-pressure stage, in order to investigate the influence of roughness on the losses over the entire stage operating envelope. Unsteady effects that may affect the influence of the roughness, such as the upcoming wakes on the rotor blade, are taken into account, and the impact of transition-related aspects on the losses is discussed.

Experimental and Numerical Study of the Response of an Axial Compressor to Distorted Inlet Flow

1988 ◽  
Vol 110 (4) ◽  
pp. 355-360 ◽  
Author(s):  
G. Billet ◽  
J. Huard ◽  
P. Chevalier ◽  
P. Laval
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Study ◽  
Axial Compressor ◽  
Numerical Approach ◽  
Compressor Blade ◽  
Numerical Results ◽  
Test Stand ◽  
Viscous Effects ◽  
Inlet Flow

A model representing the response of fixed or rotating axial compressor blade-rows is coupled to a 3-D numerical simulation of the flow outside the blade rows. The code can be used to study nonuniform compressible 3-D flows through turbomachines. The fluid is assumed to be inviscid in the space outside the rows, while the viscous effects are taken into account inside. Numerical results are compared with experimental data obtained on a test stand with steady distorted inflow. This comparison shows that this numerical approach is capable of predicting the response of the compressor. This work is part of a larger project aimed at predicting the response of a compressor to a nonuniform inlet flow that is periodic in time, or fully unsteady.

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