Modeling of transient incompressible concrete mass flow through a hose

2020 ◽

pp. 095441002094829

Author(s):

Nicolás García Rosa ◽

Adrien Thacker ◽

Guillaume Dufour

Keyword(s):

Mass Flow ◽

Turbulence Intensity ◽

Flow Separation ◽

Variable Mass ◽

Flow Coefficient ◽

Test Bed ◽

Ambient Conditions ◽

Low Velocity ◽

Blade Passing Frequency ◽

Flow Through

In a fan stage under windmilling conditions, the stator operates under negative incidence, leading to flow separation, which may present an unsteady behaviour due to rotor/stator interactions. An experimental study of the unsteady flow through the fan stage of a bypass turbofan in windmilling is proposed, using hot-wire anemometry. Windmilling conditions are reproduced in a ground engine test bed by blowing a variable mass flow through a bypass turbofan in ambient conditions. Time-averaged profiles of flow coefficient are independent of the mass flow, demonstrating the similarity of velocity triangle. Turbulence intensity profiles reveal that the high levels of turbulence production due to local shear are also independent of the inlet flow. A spectral analysis confirms that the flow is dominated by the blade passing frequency, and that the separated regions downstream of the stator amplify the fluctuations locked to the BPF without adding any new frequency. Phase-locked averaging is used to capture the periodic wakes of the rotor blades at the rotor/stator interface. A spanwise behaviour typical of flows through windmilling fans is evidenced. Through the inner sections of the fan, rotor wakes are thin and weakly turbulent, and the turbulence level remains constant through the stage. The rotor wakes thicken and become more turbulent towards the fan tip, where flow separation occurs. Downstream of the stator, maximum levels of turbulence intensity are measured in the separated flow. Large periodical zones of low velocity and high turbulence intensity are observed in the outer parts of the separated stator wake, confirming the pulsating motion of the stator flow separation, locked at the blade passing frequency. Space-time diagrams show that the flow is chorochronic, and a 2 D non-linear harmonic simulation is able to capture the main interaction modes, however, the stator incidence distribution could be affected by 3 D effects.

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Leakage flow analysis in the gas turbine shroud gap

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-01-2018-0038 ◽

2019 ◽

Vol 91 (8) ◽

pp. 1077-1085 ◽

Cited By ~ 1

Author(s):

Filip Wasilczuk ◽

Pawel Flaszynski ◽

Piotr Kaczynski ◽

Ryszard Szwaba ◽

Piotr Doerffer ◽

...

Keyword(s):

Numerical Simulation ◽

Gas Turbine ◽

Mass Flow ◽

Labyrinth Seal ◽

Leakage Flow ◽

Original Design ◽

Reference Case ◽

Content Type ◽

Flow Through ◽

The Impact

Purpose The purpose of the study is to measure the mass flow in the flow through the labyrinth seal of the gas turbine and compare it to the results of numerical simulation. Moreover the capability of two turbulence models to reflect the phenomenon will be assessed. The studied case will later be used as a reference case for the new, original design of flow control method to limit the leakage flow through the labyrinth seal. Design/methodology/approach Experimental measurements were conducted, measuring the mass flow and the pressure in the model of the labyrinth seal. It was compared to the results of numerical simulation performed in ANSYS/Fluent commercial code for the same geometry. Findings The precise machining of parts was identified as crucial for obtaining correct results in the experiment. The model characteristics were documented, allowing for its future use as the reference case for testing the new labyrinth seal geometry. Experimentally validated numerical model of the flow in the labyrinth seal was developed. Research limitations/implications The research studies the basic case, future research on the case with a new labyrinth seal geometry is planned. Research is conducted on simplified case without rotation and the impact of the turbine main channel. Practical implications Importance of machining accuracy up to 0.01 mm was found to be important for measuring leakage in small gaps and decision making on the optimal configuration selection. Originality/value The research is an important step in the development of original modification of the labyrinth seal, resulting in leakage reduction, by serving as a reference case.

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Simulation and Modeling of Flow in a Gas Compressor

Journal of Applied Mathematics ◽

10.1155/2015/682469 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7

Author(s):

Anna Avramenko ◽

Alexey Frolov ◽

Jari Hämäläinen

Keyword(s):

Steady State ◽

Mass Flow ◽

Gas Flow ◽

Simulation Method ◽

High Mass ◽

Ansys Fluent ◽

Flow Rates ◽

Mass Flow Rates ◽

Low Mass ◽

Flow Through

The presented research demonstrates the results of a series of numerical simulations of gas flow through a single-stage centrifugal compressor with a vaneless diffuser. Numerical results were validated with experiments consisting of eight regimes with different mass flow rates. The steady-state and unsteady simulations were done in ANSYS FLUENT 13.0 and NUMECA FINE/TURBO 8.9.1 for one-period geometry due to periodicity of the problem. First-order discretization is insufficient due to strong dissipation effects. Results obtained with second-order discretization agree with the experiments for the steady-state case in the region of high mass flow rates. In the area of low mass flow rates, nonstationary effects significantly influence the flow leading stationary model to poor prediction. Therefore, the unsteady simulations were performed in the region of low mass flow rates. Results of calculation were compared with experimental data. The numerical simulation method in this paper can be used to predict compressor performance.

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Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

10.2514/6.1992-2881 ◽

1992 ◽

Cited By ~ 1

Author(s):

S. PAPELL ◽

TED NYLAND ◽

NASEEM SAIYED

Keyword(s):

Mass Flow ◽

Liquid Hydrogen ◽

Flow Through ◽

Hydrogen Mass

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The Removal of the Boundary Layer of a Supersonic Flow by Means of a Slot

Journal of Applied Mechanics ◽

10.1115/1.3636524 ◽

1963 ◽

Vol 30 (2) ◽

pp. 275-278

Author(s):

M. Cloutier

Keyword(s):

Boundary Layer ◽

Mass Flow ◽

Static Pressure ◽

Free Stream ◽

Subsequent Development ◽

Displacement Thickness ◽

Free Stream Mach Number ◽

Slot Opening ◽

Flow Through ◽

Transverse Slot

The influence of slot opening and of suction pressure upon the mass flow through the slot and the subsequent development of the boundary layer has been studied for the case of a single transverse slot opening into a boundary layer with a displacement thickness of 0.168 in. at a free-stream Mach number of 2.92. The results show that as much as 85 percent of the mass flow in the boundary layer between the wall and the position of the slot lip enters the slot, and that this result is independent of the slot reservoir pressure, providing the latter is less than approximately twice the tunnel static pressure.

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ESTIMATION OF THE WATER-MASS-FLOW THROUGH A CENTRAL HEATING BOILER

IFAC Proceedings Volumes ◽

10.3182/20020721-6-es-1901.01017 ◽

2002 ◽

Vol 35 (1) ◽

pp. 187-192

Author(s):

Karsten Spreitzer ◽

Dörte Rückbrodt ◽

Harald Straky

Keyword(s):

Mass Flow ◽

Water Mass ◽

Central Heating ◽

Flow Through ◽

Heating Boiler

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Transport of Tritiated Water and 14c-Labelled Assimilate Into Grains of Wheat. III. Diffusion of Tho Through the Stalk

Functional Plant Biology ◽

10.1071/pp9850595 ◽

1985 ◽

Vol 12 (6) ◽

pp. 595 ◽

Cited By ~ 3

Author(s):

CF Jenner

Keyword(s):

Mass Flow ◽

Short Distance ◽

Vascular System ◽

Tritiated Water ◽

The Self ◽

Wheat Grain ◽

Physical Processes ◽

Self Diffusion ◽

Separate System ◽

Flow Through

Measuring the rate at which tritiated water is transported by diffusion through the stalk of the wheat grain is the main purpose of this paper. Diffusion of THO through the stalk is much slower than expected on the basis of the self-diffusion of THO in water, demonstrating that there are substantial resistances to diffusion of water in the stalk. Entry of THO into the grain by physical processes alone (diffusion), as measured in assemblies in which the grain (stripped of its bracts) is sealed into an impermeable capsule, is fast enough to account for the observed rate of transport of THO into normally functioning grains. Metabolically linked transport of water through the stalk is not detectable. Either the volume of water involved in mass flow through the stalk is too low to be detectable - which would require the concentration of sucrose to be about 2 M, or the entry of assimilate is not accompanied by water. Short-distance transfer of solute (only) from the plant's vascular system to a separate system servicing the grain seems the simplest explanation on the basis of the available evidence.

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Analysis of flowrates as a basis for the simulation of dry-running rotational positive displacement pumps

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/095440602321029436 ◽

2002 ◽

Vol 216 (12) ◽

pp. 1197-1205 ◽

Cited By ~ 1

Author(s):

K Kauder ◽

D Wenderott

Keyword(s):

Mass Flow ◽

Characteristic Number ◽

Operational Reliability ◽

Simulation System ◽

Positive Displacement ◽

Market Situation ◽

Flow Through ◽

The One ◽

New Applications ◽

Operational Behaviour

New applications improve the market situation of dry-running positive displacement pumps. The mostly empirically based design of these pumps has to take into account partly competing viewpoints. These viewpoints are energetic process optimization, on the one hand, and operational reliability, on the other hand. A simulation system can be used to solve this problem. The simulation system uses an energy and a mass balance in order to simulate the operational behaviour of the vacuum pumps. Therefore knowledge of the different states of flow through clearances in a vacuum is essential. The experimental examination of the flow is done by flood curve measurements, to describe the mass flow integrally using the characteristic number of the standardized mass flow. The results for some possible plain clearance shapes are discussed.

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