Numerical Study of Flow Through 3x3 Multiswirler Arrays With Co and Counter Swirler Arrangements

2015 ◽  
Author(s):  
Prachi Rojatkar ◽  
Milind A. Jog ◽  
San-Mou Jeng
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Turbulence Model ◽  
Velocity Gradient ◽  
Recirculation Zone ◽  
Numerical Study ◽  
The Other ◽  
Combustion Performance ◽  
Other Hand ◽  
Flow Through

A numerical study of turbulent flow through 3×3 multi swirler arrangement has been performed using the realizable k-ε turbulence model on a grid with about 19 million points. All co and alternate co/counter swirler configurations comprised of radial-radial swirler with counter rotating vanes are analyzed. The offset distances of swirler exit from the base wall of confinement of 0.02D and 0.31D are considered where D is the diameter of swirler exit. For both arrangements, a strong jet is issued as the flow exits individual swirl cup. Recirculation is observed at the walls and between each swirl cup along with the formation of central toroidal recirculation zone (CTRZ) at each individual swirler. It is observed that all co swirling arrangement has a stronger more compact individual CTRZ. On the other hand alternate co and counter arrangement produces more swirler-to-swirler interactions. When the offset between swirler exit and base wall of confinement is increased to 0.31D, longer but more compact CTRZ are formed at each swirler cup. The velocity gradient for 0.31D offset case is also higher than that of 0.02D. These differences in the flow field indicate better combustion performance, fuel breakup and flame anchoring for the higher offset case.

scholarly journals Blood Perfusion of the Kidney of Lophius Piscatorius L.

1953 ◽  
Vol 32 (2) ◽  
pp. 329-336 ◽  
Author(s):  
L. Brull ◽  
E. Nizet ◽  
E. B. Verney
Keyword(s):  
Blood Flow ◽  
Critical Level ◽  
Perfusion Pressure ◽  
Blood Perfusion ◽  
Urine Flow ◽  
The Other ◽  
Protein Nitrogen ◽  
Other Hand ◽  
Flow Through

Lophius kidneys perfused with the heparinized blood (venous) of the fish secrete urine in which total non-protein nitrogen is concentrated, magnesium highly concentrated, and chloride only slightly so or not at all. Oxygenation of the blood, or lowering the temperature of the perfusate from c. 20° to c. 5° C. does not appear to influence secretion. The blood flow through the kidneys increases with the perfusion pressure, the increase often becoming disproportionately large. The urine flow, on the other hand, above a certain critical level is largely independent of changes in perfusion pressure.

scholarly journals Distribution of velocity and temperature between concentric rotating cylinders

1935 ◽  
Vol 151 (874) ◽  
pp. 494-512 ◽  
Keyword(s):  
Turbulent Flow ◽  
Velocity Distribution ◽  
The Other ◽  
Momentum Transport ◽  
Rotating Cylinders ◽  
Simultaneous Measurements ◽  
Other Hand ◽  
Vorticity Transport

It is not possible to distinguish between the Momentum Transport and the Vorticity Transport theories of turbulent flow by measurements of the distribution of velocity in a fluid flowing under pressure through pipes or between parallel planes. Only simultaneous measurements of temperature and velocity distribution are capable of distinguishing between the two theories in these cases. On the other hand, it will be seen later that measurements of the distribution of velocity between concentric rotating cylinders are capable of distinguishing between the two theories; in fact the predictions of the two theories in this case are sharply contrasted and mutually exclusive.

scholarly journals Effect of Prandtl number on heat transfer characteristics in an axisymmetric sudden expansion: A numerical study

2007 ◽  
Vol 11 (4) ◽  
pp. 171-178
Author(s):  
Khalid Alammar
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Prandtl Number ◽  
Turbulent Flow ◽  
Turbulence Model ◽  
Numerical Study ◽  
Sudden Expansion ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Simulated Effect

Using the standard k-e turbulence model, an incompressible, axisymmetric turbulent flow with a sudden expansion was simulated. Effect of Prandtl number on heat transfer characteristics downstream of the expansion was investigated. The simulation revealed circulation downstream of the expansion. A secondary circulation (corner eddy) was also predicted. Reattachment was predicted at approximately 10 step heights. Corresponding to Prandtl number of 7.0, a peak Nusselt number 13 times the fully-developed value was predicted. The ratio of peak to fully-developed Nusselt number was shown to decrease with decreasing Prandtl number. Location of maximum Nusselt number was insensitive to Prandtl number.

Significant of Isothermal Flow Studies for High Swirling Flow in Unconfined Burner

2015 ◽  
Vol 789-790 ◽  
pp. 477-483
Author(s):  
A.R. Norwazan ◽  
M.N. Mohd Jaafar
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Turbulent Flows ◽  
Recirculation Zone ◽  
Swirling Flow ◽  
Numerical Study ◽  
Tangential Velocity ◽  
Radial Distance ◽  
Navier Stokes ◽  
Reacting Flow

This paper is presents numerical simulation of isothermal swirling turbulent flows in a combustion chamber of an unconfined burner. Isothermal flows of with three different swirl numbers, SN of axial swirler are considered to demonstrate the effect of flow axial velocity and tangential velocity to define the center recirculation zone. The swirler is used in the burner that significantly influences the flow pattern inside the combustion chamber. The inlet velocity, U0 is 30 m/s entering into the burner through the axial swirler that represents a high Reynolds number, Re to evaluate the differences of SN. The significance of center recirculation zone investigation affected by differences Re also has been carried out in order to define a good mixing of air and fuel. A numerical study of non-reacting flow into the burner region is performed using ANSYS Fluent. The Reynolds–Averaged Navier–Stokes (RANS) realizable k-ε turbulence approach method was applied with the eddy dissipation model. An attention is focused in the flow field behind the axial swirler downstream that determined by transverse flow field at different radial distance. The results of axial and tangential velocity were normalized with the U0. The velocity profiles’ behaviour are obviously changes after existing the swirler up to x/D = 0.3 plane. However, their flow patterns are similar for all SN after x/D = 0.3 plane towards the outlet of a burner.

Numerical Investigations on Effect of Inflow Parameters on Development of Secondary Flow Field for Linear LP Turbine Cascade

2021 ◽  
Author(s):  
Anand P. Darji ◽  
Beena D. Baloni ◽  
Chetan S. Mistry
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Turbulence Model ◽  
Turbulence Intensity ◽  
Numerical Study ◽  
Turbine Cascade ◽  
Wall Flow ◽  
End Wall ◽  
Inflow Conditions ◽  
Secondary Flow Field

Abstract End wall flows contribute the most crucial role in loss generation for axial flow turbine and compressor blades. These losses lead to modify the blade loading and overall performance in terms of stable operating range. Present study aimed to determine the end wall flow streams in a low speed low pressure linear turbine cascade vane using numerical approach. The study includes two sections. The first section includes an attempt to understand different secondary flow streams available at end wall. Location of generation of horseshoe vortex streams and subsequent vortex patterns are identified in the section. The selection of suitable turbulence model among SST (Shear Stress Transport) k–ω and SST γ–θ to identify end wall flow streams is studied in prior in the section. The steady state numerical study is performed using Reynolds Averaged Navier-Stoke’s Equations closed by SST γ–θ turbulence model. The computational results are validated with experimental results available in the literature and are found to be in good agreement. The study is extended for different inflow conditions in later section. The second section includes effect of flow incidence and turbulence intensity on the end wall secondary flow field. Inflow incidences considered for the study are −20°, −10°, 0° (design incidence), +10° and +20°. The inlet turbulence intensities are varied by 1% and 10% for each case. The results revealed different secondary flow patterns at an end wall and found the change in behavior with an inflow conditions. SST γ–θ turbulence model with lower turbulence intensity is more suitable to identify such flow behavior.

Numerical Study of the inside Flow Field and the Rectangle Channel Impeller of Roto-Jet Pump

2014 ◽  
Vol 529 ◽  
pp. 164-168 ◽  
Author(s):  
Wei Zang ◽  
Xin Cheng Li ◽  
Yi Chen ◽  
Yu Ting Luo
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Numerical Study ◽  
The Other ◽  
Jet Pump ◽  
Hydraulic Models ◽  
Flow Channels ◽  
Ansys Cfx ◽  
Angle Blade

By means of ANSYS-CFX, the 3D numerical simulations of flow field for the three hydraulic models are performed. Through comparing the three types of pumps with three different rectangle channel impellers which have different spread angle, blade, the authors draw conclusions: the distribution of the pressure and velocity in the rectangle flow channels with 6° spread angle is well-proportioned, the head and the efficiency of the whole pump can meet the requirement: But the other two types of impeller channels, the distribution of velocity is unstable, there are backflow and big whirlpool. Therefore, the rectangle channel impeller with 6°spread angle is a better type for the Roto-Jet pump.

Experimental and Numerical Investigation on the Aerodynamic Performance of a Compressor Cascade Using Blended Blade and End Wall

2017 ◽  
Author(s):  
Jiabin Li ◽  
Lucheng Ji ◽  
Weilin Yi
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Turbulence Model ◽  
Numerical Study ◽  
Incidence Angle ◽  
Good Effect ◽  
Compressor Cascade ◽  
Corner Separation ◽  
Sst Turbulence Model ◽  
End Wall

Nowadays, the corner separation, occurring near the corner region formed by the suction surface of blade and end wall, has been an important limitation for the increasing of the aerodynamic loading in the compressor. The previous numerical studies indicate that the Blended Blade and End Wall (BBEW) technology is useful in delaying, or reducing, or even eliminating the corner separation. To further validate the concept, this paper presents combined experimental and numerical investigations on a BBEW cascade and its prototype. Firstly, the NACA65 linear compressor cascade with the turning angle 42 degrees was designed and tested in a low-speed wind tunnel. Then, the cascade with blended blade and end wall design was made and tested in the same wind tunnel. The experimental results show that the design of blended blade and end wall can improve the performance of the cascade when the incidence angle was positive or at the design point, and the total pressure loss coefficient was reduced by 7%–8%. The performance improvement mainly located from 10%–25% span heights. Secondly, based on the experimental data, the numerical study made by our internal code Turbo-CFD shows the difference of the simulation precision of the results, obtained from four different turbulence model after the mesh independence test. The four turbulence model is Spalart-Allmaras model, standard k-ε model, standard k-ω model, and shear stress transport k-ω model. For this case, the SST turbulence model has better performance compared with others. Thirdly, based on the results which were calculated with the turbulence model SST, the effect of the blended blade and end wall design was discussed. The numerical study shows that the design with the blended blade and end wall can have a good effect on the corner flow of the cascade. The strong three-dimensional corner separation, caused by the accumulation of the flow happening at the trail of the suction side was avoided, and the flow losses of the prototype cascade were reduced. Above all, the experiment shows that the design with blended blade and end wall can improve the performance of the cascade. Compared with the experiment data, the SST turbulence model shows the best results of the flow field. Based on the numerical results, the details of the flow field and the effect of the blended blade and end wall design on the corner separation are discussed and analyzed.

The Effect of Velocity in High Swirling Flow in Unconfined Burner

2014 ◽  
Vol 69 (6) ◽  
Author(s):  
Norwazan A. R ◽  
Mohammad Nazri Mohd. Jaafar
Keyword(s):  
Flow Field ◽  
Turbulent Flows ◽  
Recirculation Zone ◽  
Swirling Flow ◽  
Numerical Study ◽  
Tangential Velocity ◽  
Reacting Flow ◽  
Ansys Fluent ◽  
Inlet Velocity ◽  
Burner Exit

This paper presents a numerical simulation of swirling turbulent flows in combustion chamber of unconfined burner. Isothermal flows with three different swirl numbers using axial swirler are used to demonstrate the effect of flow in axial velocity and tangential velocity on the center recirculation zone. The significance of center recirculation zone is to ensure a good mixing of air and fuel in order to get a better combustion. The inlet velocity, U0 is 30 m/s entering into the burner through the axial swirler that is represents a high Reynolds number. A numerical study of non-reacting flow in the burner region is performed using ANSYS Fluent. The Reynolds–Averaged Navier–Stokes (RANS) standard k-ε turbulence approach method was applied with the eddy dissipation model. The paper focuses the flow field behind the axial swirler downstream that determined by transverse flow field at different on radial distances. The results of axial and tangential velocity were normalized with the inlet velocity. The velocity profiles are different after undergoing the different swirler up to the burner exit. However, the results of velocity profile showed that the high SN gives a better swirling flow patterns. 

Sign in / Sign up

Export Citation Format

Share Document