Choking Phenomena in a Vortex Flow Passing a Laval Tube: An Analytical Treatment

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Theo Van Holten ◽  
Monique Heiligers ◽  
Annemie Jaeken
Keyword(s):  
Numerical Simulation ◽  
Vortex Flow ◽  
Laval Nozzle ◽  
Analytical Theory ◽  
Axial Component ◽  
Nozzle Throat ◽  
Analytical Treatment ◽  
Test Channel ◽  
Flow Through ◽  
Total Velocity

The behavior of a vortex flow through a Laval nozzle was studied in connection with the purification of natural gas. By creating a vortex and passing it through a Laval nozzle, the gas will be cooled, and water droplets will form and will be centrifuged out of the gas. This system is named the Condi-Cyclone. An analytical theory is developed to reveal the most important phenomena of the flow, to first order accuracy. Experiments have been performed with a prototype of the Condi-Cyclone. A Euler numerical simulation was performed, using the geometry of the test channel. This paper presents an analytical theory for a vortex flow through a Laval nozzle. It will demonstrate that when a vortex is present the total velocity reaches sonic conditions upstream of the nozzle throat, that the axial component of the velocity in the nozzle throat is equal to the local speed of sound and that the mass flow through the Laval nozzle decreases with increasing vortex strength. The predictions of the analytical theory have been compared with the results of the experiments and the Euler numerical simulation, and it can be concluded that the analytical theory describes the main characteristics of the flow very well.

Enhanced vortex stability in trapped vortex combustor

2010 ◽  
Vol 114 (1155) ◽  
pp. 333-337 ◽  
Author(s):  
S. Vengadesan ◽  
C. Sony
Keyword(s):  
Numerical Simulation ◽  
Vortex Flow ◽  
Cavity Size ◽  
Vortex Stability ◽  
Cold Flow ◽  
Air Jets ◽  
Passive Flow ◽  
Flow Through ◽  
Trapped Vortex ◽  
Driver Air

Abstract The Trapped Vortex Combustor (TVC) is a new design concept in which cavities are designed to trap a vortex flow structure established through the use of driver air jets located along the cavity walls. TVC offers many advantages when compared to conventional swirl-stabilised combustors. In the present work, numerical investigation of cold flow (non-reacting) through the two-cavity trapped vortex combustor is performed. The numerical simulation involves passive flow through the two-cavity TVC to obtain an optimum cavity size to trap stable vortices inside the second cavity and to observe the characteristics of the two cavity TVC. From the flow attributes, it is inferred that vortex stability is achieved by circulation and the vortex is trapped inside when a second afterbody is added.

Laminar Flow through a Rectangular Horizontal Channel with Asymmetrical Contraction

2009 ◽  
Vol 15 ◽  
pp. 21-26
Author(s):  
O.A. Morales-Contreras ◽  
J.G. Barbosa-Saldaña ◽  
J.A. Jiménez-Bernal ◽  
Claudia del Carmen Gutiérrez Torres
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Step Height ◽  
Axial Component ◽  
Parabolic Profile ◽  
Flow Through ◽  
Stream Direction

Numerical simulation for the three-dimensional laminar flow through a forward facing step channel was simulated by Fluent 6.3 code. Four Reynolds numbers and four step lengths were analyzed. The results showed that the length of the recirculation zone upstream the step depends on Reynolds number, as well as on the step height (h), while the height of the recirculation zone extends about 70% of the step height. In addition, it was found that the velocity profile in the stream direction at the channel exit presents a fully developed profile for the axial component. Nonetheless, the profile along the transversal direction does not have a parabolic profile, even for a length of 60h

scholarly journals Study on the Convective Heat Transfer and Fluid Flow of Mini-Channel with High Aspect Ratio of Neutron Production Target

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4020
Author(s):  
Peng Sun ◽  
Yiping Lu ◽  
Jianfei Tong ◽  
Youlian Lu ◽  
Tianjiao Liang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Aspect Ratio ◽  
Optimization Design ◽  
Heat Dissipation ◽  
Neutron Production ◽  
Thermal Design ◽  
Maximum Deviation ◽  
Test Channel ◽  
Production Target

In order to provide a theoretical basis for the thermal design of the neutron production target, flow and heat transfer characteristics are studied by using numerical simulations and experiments. A rectangular mini-channel experimental model consistent with the geometric shape of the heat dissipation structure of neutron production target was established, in which the aspect ratio and gap thickness of the test channel were 53.8:1 and 1.3 mm, respectively. The experimental results indicate that the critical Re of the mini-channel is between 3500 and 4000, and when Re reaches 21,000, Nu can reach 160. The simulation results are in good agreement with the experimental data, and the numerical simulation method can be used for the variable structure optimization design of the target in the later stage. The relationship between the flow pressure drop of the target mini-channel and the aspect ratio and Re is obtained by numerical simulation. The maximum deviation between the correlation and the experimental value is 6%.

UCBO Hydraulic Oil and Application on Hydraulic Measurement for Laval Nozzle Throat Diameter

2015 ◽  
Vol 667 ◽  
pp. 449-454
Author(s):  
Yang Hong ◽  
Xiang Zhang ◽  
Dong Xiang Shao ◽  
Guang Lin Wang ◽  
Li Sun
Keyword(s):  
Laval Nozzle ◽  
Oxidation Stability ◽  
Measurement Model ◽  
Diameter Measurement ◽  
Liquid Pressure ◽  
Nozzle Throat ◽  
Hydraulic Oil ◽  
Temperature Performance ◽  
Measurement Principle ◽  
Throat Diameter

This paper proposes a hydraulic measurement model for measuring the Laval nozzle throat diameter size. Based on measurement principle of liquid pressure – flowrate, we can get the size of Laval nozzle throat diameter by measuring the fluid flowrate through hydraulic measurement model at the fixed pressure. With good viscosity-temperature performance, low temperature performance and oxidation stability, UCBO aviation hydraulic oil is selected as the measuring medium. In the hydraulic measurement model, the diameter of the mandrel which can be regarded as gauge will directly affect the sensitivity of diameter measurement. Therefore we need to optimize the design of the mandrel of the hydraulic model.

Numerical Simulation Analysis for Scroll of Scroll Compressor Based on ABAQUS

2014 ◽  
Vol 488-489 ◽  
pp. 1047-1051
Author(s):  
Qing Qian Zheng ◽  
Bin Yang ◽  
Ning Chen ◽  
Hui Min Yang ◽  
Min Hu
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Thermal Deformation ◽  
Vortex Flow ◽  
Simulation Analysis ◽  
Temperature Load ◽  
Stress And Deformation ◽  
Finite Method ◽  
Abaqus Software ◽  
Main Factor

In this paper, the finite method is applied and ABAQUS software is used, the vortex flow field is loaded as boundary condition of wraps. The stress and deformation in scroll under the action of gas pressure, temperature load and both of them is analyzed, the stress distribution and deformation of wraps in different shaft rotation angles is discussed, the stress distribution and deformation discipline of wraps are also respectively obtained. The results show that the overall stress and deformation in scroll are the largest when compression chamber is moving near the vent position and the thermal deformation is the main factor of affecting the overall deformation of scroll.

scholarly journals Numerical simulation of the accumulation of heavy particles in a circular bounded vortex flow

2016 ◽  
Vol 87 ◽  
pp. 80-89 ◽  
Author(s):  
Xiaoke Ku ◽  
Jianzhong Lin ◽  
Martin van Sint Annaland ◽  
Rob Hagmeijer
Keyword(s):  
Numerical Simulation ◽  
Vortex Flow ◽  
Heavy Particles
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