scholarly journals Ice slurry flow through gate valves – local pressure loss coefficient

2019 ◽  
Vol 214 ◽  
pp. 012112
Author(s):  
M Sołek ◽  
Ł Mika
Keyword(s):  
Pressure Loss ◽  
Loss Coefficient ◽  
Ice Slurry ◽  
Slurry Flow ◽  
Local Pressure ◽  
Pressure Loss Coefficient ◽  
Flow Through

scholarly journals Determination of the Local Pressure Loss Coefficient Experimentally and Using CFD Methods

2020 ◽  
Vol 328 ◽  
pp. 02019
Author(s):  
Šimon Kubas ◽  
Andrej Kapjor ◽  
Martin Vantúch ◽  
Marián Pafčuga
Keyword(s):  
Pressure Loss ◽  
Air Conditioning ◽  
Loss Coefficient ◽  
Cfd Model ◽  
Acoustic Attenuation ◽  
Local Pressure ◽  
High Noise ◽  
Pressure Losses ◽  
Pressure Loss Coefficient

When choosing silencers in air conditioning, it is necessary to pay attention not only to the acoustic attenuation, but also to the pressure loss of the silencer. If the pressure loss of the damper is too high, noise will occur directly in the damper. The pressure losses of the silencers are determined mainly experimentally. Based on the performed measurement, a CFD model of the selected silencer was constructed, where the influence of various parameters on the value of the pressure loss of the selected silencer was investigated.

A Study on Performance Characteristics for Closed Brayton Cycle in Inventory Regulation

2014 ◽  
Author(s):  
Huijing Jiang ◽  
Xiaoyong Yang ◽  
Ming Ding ◽  
Jie Wang
Keyword(s):  
High Temperature ◽  
Mass Flow ◽  
Pressure Loss ◽  
Loss Coefficient ◽  
Performance Characteristics ◽  
Brayton Cycle ◽  
Local Pressure ◽  
Pressure Loss Coefficient ◽  
Test Reactor ◽  
High Temperature Gas

High temperature gas-cooled reactor combined with gas turbine cycle can make full use of the high outlet helium temperature of reactor. Compared to the Open Brayton Cycle, inventory regulation is a new regulation method for Closed Brayton Cycle, which can control the output power of the cycle through the change of pressure level and mass flow of the system. Taking the 10MW high temperature gas-cooled test reactor coupled with helium-turbine cycle (HTR-10GT) for example, a more practice-oriented resistance model is established in this paper for the analysis of influence of resistance characteristic on key components and closed Brayton cycle. When helium inventory drops from 100% to 30% of rated value, the mass flow rate of helium decreases, so the local pressure loss coefficient keeps constant and the pressure loss coefficient increases. As a result, the efficiency of closed cycle decreased about 15%. The performance characteristics of the turbomachinery and heat exchangers are also discussed in detail as key components in the power conversation unit (PCU).

HEMODYNAMICS IN STENOSED ARTERIES — EFFECTS OF STENOSIS SHAPES

2010 ◽  
Vol 07 (03) ◽  
pp. 397-419 ◽  
Author(s):  
MOLOY K. BANERJEE ◽  
DEBABRATA NAG ◽  
RANJAN GANGULY ◽  
AMITAVA DATTA
Keyword(s):  
Pressure Loss ◽  
Reynolds Numbers ◽  
Loss Coefficient ◽  
Centerline Velocity ◽  
Hemodynamic Parameters ◽  
Gaussian Shape ◽  
Pressure Loss Coefficient ◽  
Flow Through ◽  
Recirculation Length ◽  
Hemodynamic Flow

A numerical analysis has been carried out to investigate the hemodynamic flow through stenosed arteries having mild (S = 25%) to severe (S = 65%) occlusions and under different regimes of flow Reynolds numbers ( Re ) ranging from 50 to 400. Influence of different stenosis shapes (rectangular, trapezoidal, cosine, and Gaussian) on key hemodynamic parameters e.g., recirculation length, wall shear stress (WSS), pressure drop, and irreversible pressure loss coefficient (C I ) are studied. It has been observed that for S = 25%, no flow separation takes place with cosine and Gaussian shaped stenoses for all the Re values considered, while for rectangular or trapezoidal shapes the flow begins to separate at Re = 400. At higher degrees of stenosis, post-stenotic recirculation is noticed for all the shapes considered — the largest recirculation length being observed with the rectangular shape. The peak centerline velocity in the stenosed region is more sensitive to a change in the degree of occlusion for rectangular stenosis than the other shapes. From the study, it is also revealed that the irreversible pressure loss coefficient (C I ) is the maximum for rectangular shaped stenosis, while it is the least for Gaussian shape. It is observed that at high Re regime, C I becomes insensitive to Re values and can be approximated to be a function of the degree of stenosis (S) and the stenosis shape only.

Vibration suppression investigation and parametric design of tri-axle straight heavy truck with pitch-resistant hydraulically interconnected suspension

2021 ◽  
pp. 107754632110396
Author(s):  
Fei Ding ◽  
Jie Liu ◽  
Chao Jiang ◽  
Haiping Du ◽  
Jiaxi Zhou ◽  
...  
Keyword(s):  
Surface Area ◽  
Dynamic Load ◽  
Pressure Loss ◽  
Vibration Suppression ◽  
Parametric Design ◽  
Suspension System ◽  
Loss Coefficient ◽  
The Body ◽  
Impedance Matrix ◽  
Pressure Loss Coefficient

The vibration suppression of the proposed pitch-resistant hydraulically interconnected suspension system for the tri-axle straight truck is investigated, and the vibration isolation performances are parametrically designed to achieve smaller body vibration and tire dynamic load using increased pitch stiffness and optimized pressure loss coefficient. For the hydraulic subsystem, the transfer impedance matrix method is applied to derive the impedance matrix. These hydraulic forces are incorporated into the motion equations of mechanical subsystem as external forces according to relationships between boundary flow and mechanical state vectors. In terms of the additional mode stiffness/damping and suspension performance requirements, the cylinder surface area, accumulator pressure, and damper valve’s pressure loss coefficient are comprehensively tuned with parametric design technique and modal analysis method. It is found the isolation capacity is heavily dependent on installation scheme and fluid physical parameters. Especially, the surface area can be designed for the oppositional installation to separately raise pitch stiffness without increasing bounce stiffness. The pressure loss coefficients are tuned with design of experiment approach and evaluated using all conflict indexes with normalized dimensionless evaluation factors. The obtained numerical results indicate that the proposed pitch-resistant hydraulically interconnected suspension system can significantly inhibit both the body and tire vibrations with decreased suspension deformation, and the tire dynamic load distribution among wheel stations is also improved.

The Characteristics Study of Helium-Xenon Mixture in Closed Brayton Cycle for Space Nuclear Reactor Power

2018 ◽  
Author(s):  
Xie Yang ◽  
Lei Shi
Keyword(s):  
Physical Properties ◽  
Pressure Loss ◽  
Nuclear Reactor ◽  
Reactor Power ◽  
Loss Coefficient ◽  
Working Fluid ◽  
System Efficiency ◽  
Pressure Loss Coefficient ◽  
Molar Weight ◽  
Xenon Mixture

Differing from the adoption of helium as working fluid of closed Brayton cycle (CBC) for terrestrial high temperature gas cooled reactor (HTGR) power plants, helium-xenon mixture with a proper molar weight was recommended as working fluid for space nuclear reactor power with CBC conversion. It is essential to figure out how the component of helium-xenon mixture affects the net system efficiency, in order to provide reference for the selection of appropriate cycle working fluid. After a discussion of the physical properties of different helium-xenon mixtures, the related physical properties are studied to analyze their affection on the key parameters of CBC, including adiabatic coefficient, recuperator effectiveness and normalized pressure loss coefficient. Then the comprehensive thermodynamics of CBC net system efficiency is studied in detail considering different helium-xenon mixtures. The physical properties study reveals that at 0.7 MPa and 400 K, the adiabatic coefficient of helium-xenon mixture increases with increased molar weight, from 0.400 (pure helium) to 0.414 (pure xenon), while recuperator effectiveness firstly increases and then decreases with the increase of molar weight, and the normalized pressure loss coefficient increases monotonically with molar weight increases. The thermodynamic analysis results show that the adiabatic coefficient has less effect on the net system efficiency, while the net system efficiency increases with increased recuperator effectiveness, and the net system efficiency decreases with normalized pressure loss coefficient increases. Finally, the mixture of helium-8.6% xenon was adopted as working fluid, instead of pure helium, for ensuring less turbine mechanicals (turbine and compressor) stages, and resulting maximum recuperator effectiveness. At the given cold / hot side temperature of 400 / 1300 K, the net system efficiency can reach 29.18% theoretically.

Rotating Annulus Component Performance Characterisation Based on CFD Analyses

2018 ◽  
Author(s):  
Youming Yuan ◽  
David Hunt
Keyword(s):  
Test Data ◽  
Pressure Loss ◽  
Model Performance ◽  
Internal Flow ◽  
Loss Coefficient ◽  
Performance Data ◽  
Pressure Loss Coefficient ◽  
1D Model ◽  
Torque Coefficient ◽  
Secondary Air

FloMASTER is a 1-D thermo-fluids system simulation tool and its component models depend on the characterisation data of the component performance. Such performance data is mainly based on data banks established from extensive tests exemplified by the books like “Internal Flow” by Miller [1] and “Handbook of Hydraulic Resistance” by Idelchik [2]. One of the key components of the gas turbine secondary air system is the rotating annulus. However, reliable data and correlations for performance characteristics like pressure loss coefficient, torque coefficient, windage and heat transfer for this component are rare and non-existent in the open literature for the case of both walls rotating simultaneously, which is becoming more common in today’s multi-spool military aero engines. To overcome this challenge of lack of reliable performance data and correlations, in this paper the Mentor Graphics 3D CFD tool “FloEFD” is used to model both inner wall rotating and outer wall rotating annulus flow, and to verify the 3D CFD results of performance data in terms of pressure loss coefficient and torque coefficient versus some published test data in the open literature. It is shown that the CFD gives results on pressure loss and torque coefficients that are in good agreement with test data based correlations used in FloMASTER. This demonstrates that 3D CFD can be used as a powerful tool for verifying the existing 1D model, extending the 1D model performance data range and generating new performance data for developing new components where such data is not available from open literature. A future project is to extend this approach to provide performance data for rotating annuli with both walls rotating. Such data will form the basis for developing a new component model for a rotating annulus with both walls rotating.

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