764. Theoretical and experimental studies of the underlying processes and techniques of low pressure measurements

Vacuum ◽  
1967 ◽  
Vol 17 (4) ◽  
pp. 248
Keyword(s):  
Experimental Studies ◽  
Low Pressure ◽  
Pressure Measurements ◽  
Underlying Processes

scholarly journals EXPERIMENTAL FACILITY FOR THE STUDY OF THE PROCESSES IN MIXING LOW-PRESSURE HEATERS OF K-1000-60/3000 TURBINES

2020 ◽  
Vol 2 (61) ◽  
pp. 42-50
Author(s):  
A. Smychok ◽  
◽  
V. Gerliga ◽  
V. Zaporozhan ◽  
M. Panchenko ◽  
...  
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Experimental Studies ◽  
Operating Experience ◽  
Low Pressure ◽  
Main Task ◽  
Experimental Facility ◽  
Design Features ◽  
Technical Problems ◽  
Hydraulic Processes

Nowadays, the development of nuclear energy is determined by solving the set of scientific and technical problems that provides reliable, safe and sustainable work of the operated and designed NPPs. At the same time different accident conditions and likelihood (probability) of variant equipment operating failures are analyzed. Obtained operating experience of the mixing low-pressure heaters (LPH) at thermal power plants (TPP) and NPPs shows that pulsations occur in some operation regimes of LPH turbine which lead to inner element destructions of LPH and pipeline malfunctions. These circumstances negatively affect operation of equipment that locates after LPH in condensate-supply tract. Consequently, unit capacity factor and economic indicators descend since troubleshooting for LPH mechanisms require some time and material resources. This work presents the experimental facility design and description of main design features of the facility components. The stand was designed to study the processes that lead to the vibration appearance in mixing LPH in condensate-supply tract of K-1000-60/3000 turbines. The main task of scale modeling is the need to observe equivalent conditions of the thermal-hydraulic processes behavior in the model in relation to full-scale equipment. To solve this problem using ANSYS code a preliminary simulation of hydraulic processes occurring in the experimental facility was performed. This allowed to determine in advance certain design features in the design of given facility. The results of experimental studies of the developed facility should allow to develop measures for reduction or complete elimination of vibrations in mixing LPH, as well as to validate computer programs for design analysis of stationary and non-stationary thermal-hydraulic processes in the specified equipment and designed measures testing.

Pressure and Its Measurement

2011 ◽  
pp. 1-11
Author(s):  
James R. Munis
Keyword(s):  
Volume Change ◽  
Low Pressure ◽  
Body Fluids ◽  
Fundamental Difference ◽  
Pressure Measurements ◽  
Mechanical Pressure ◽  
Semantic Point

In physiologic terms, we are exposed to 3 main sources of pressure: 1) the weight of the atmosphere; 2) hydrostatic forces exerted by the weight of body fluids; and 3) mechanical pressure generated by the heart or other muscles that contract around those fluids. Because cardiopulmonary physiology deals so much with pressure measurements, let's start by defining what pressure really is. Simply put, pressure is force divided by area. It's also important to understand what pressure is not. For example, pressure is not energy. Only when pressure is coupled to a volume change (ie, movement or pressure-volume work) is it a component of energy. This is more than just a semantic point. Although we're fond of saying that fluids move from high to low pressure, that isn't always true. The reason why highlights a fundamental difference between pressure and energy. Pressure is surprisingly difficult to measure. Often, when we think we are measuring pressure, we are actually measuring stretch or movement.

scholarly journals A Fabry-Perot sensor prototype for low-pressure measurements

2014 ◽  
Vol 56 (12) ◽  
pp. 2981-2986 ◽  
Author(s):  
P. Roriz ◽  
M. S. Ferreira ◽  
K. Schuster ◽  
J. Kobelke ◽  
O. Frazão
Keyword(s):  
Low Pressure ◽  
Pressure Measurements ◽  
Fabry Perot

The Effect of Wake Passing on a Flow Separation in a Low-Pressure Turbine Cascade

2004 ◽  
Vol 126 (2) ◽  
pp. 250-256 ◽  
Author(s):  
Michael J. Brear ◽  
Howard P. Hodson
Keyword(s):  
Separation Bubble ◽  
Phase Locking ◽  
Experimental Studies ◽  
Leading Edge ◽  
Low Pressure ◽  
Pressure Surface ◽  
Low Pressure Turbine ◽  
Numerical Predictions ◽  
Unsteady Interaction ◽  
Wake Passing

This paper describes an investigation into the effect that passing wakes have on a separation bubble that exists on the pressure surface and near the leading edge of a low-pressure turbine blade. Previous experimental studies have shown that the behavior of this separation is strongly incidence dependent and that it responds to its disturbance environment. The results presented in this paper examine the effect of wake passing in greater detail. Two-dimensional, Reynolds averaged, numerical predictions are first used to examine qualitatively the unsteady interaction between the wakes and the separation bubble. The separation is predicted to consist of spanwise vortices whose development is in phase with the wake passing. However, comparison with experiments shows that the numerical predictions exaggerate the coherence of these vortices and also overpredict the time-averaged length of the separation. Nonetheless, experiments strongly suggest that the predicted phase locking of the vortices in the separation onto the wake passing is physical.

Experimental studies on low pressure deflagration limit of ammonium perchlorate with additives

2019 ◽  
Vol 207 ◽  
pp. 356-367 ◽  
Author(s):  
Kumar Nagendra ◽  
Mahesh Ingole ◽  
Ramakrishna A. Periyapatna
Keyword(s):  
Ammonium Perchlorate ◽  
Experimental Studies ◽  
Low Pressure

Validation of Surface Pressure Predictions for Nozzle Airfoil and Endwall Film Cooling Design Using Transonic Cascade Measurements

2013 ◽  
Author(s):  
Jason E. Dees ◽  
James A. Tallman ◽  
Michael A. Heminger ◽  
Daniel Wilde
Keyword(s):  
Surface Pressure ◽  
Film Cooling ◽  
Static Pressure ◽  
Experimental Studies ◽  
Tangential Direction ◽  
Maximum Deviation ◽  
Pressure Measurements ◽  
Local Flow ◽  
Cooling Design ◽  
Transonic Cascade

This study compares surface pressure measurements and predictions for a high pressure turbine first-stage nozzle vane. The surface pressure measurements were taken in a 3D annular cascade, consisting of four airfoils and five passages. The cascade was uncooled, axisymmetric at both inner and outer endwalls, and reproduced the design intent Reynolds and Mach numbers of the real engine component. Static pressure measurements were taken along the airfoil profile at 15, 50, and 85% span, with duplicate midspan measurements across the four airfoils for assessing the tangential periodicity of the flow. Static pressure measurements were also taken on the inner and outer endwall surfaces of the center airfoil passage, with 40 measurement points uniformly distributed over each endwall. Three methods of surface pressure prediction were compared with the data: (1) a 2D inviscid CFD solution of a single airfoil passage at fixed spanwise locations, (2) a 3D RANS CFD solution of a single airfoil passage, and (3) a 3D RANS CFD solution of the full five-passage cascade domain. Both of the single-passage solutions assumed flowfield periodicity in the tangential direction and compared favorably to the center passage airfoil data. This finding suggested that the cascade center passage was sufficiently representative of the full-annulus turbomachine environment and validated the cascade for further experimental studies. The adjacent airfoil pressure measurements quantified the passage-to-passage variation in the cascade flowfield, and the 3D full-cascade CFD compared favorably with the peripheral airfoil data. The full-cascade CFD also compared favorably with the data on both endwalls: with an average and maximum deviation of 0.5 and 2%, respectively. These findings provide confidence in the 3D CFD methods for use in determining local flow rates from cooling/leakage geometry, and serve as an important first step toward validating the methods for real-engine blockage effects like coolant and endwall contouring.

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