Numerical investigations on swirl intensity decay rate for turbulent swirling flow in a fixed pipe

2011 ◽  
Vol 53 (10) ◽  
pp. 801-811 ◽  
Author(s):  
A.F. Najafi ◽  
S.M. Mousavian ◽  
K. Amini
Keyword(s):  
Decay Rate ◽  
Swirling Flow ◽  
Numerical Investigations ◽  
Swirl Intensity ◽  
Intensity Decay

Numerical Analysis of the Swirl Intensity Decay Rate for Internal Turbulent Swirling Flow

2007 ◽  
Author(s):  
A. F. Najafi ◽  
S. M. Mousavian ◽  
M. H. Saidi
Keyword(s):  
Decay Rate ◽  
Swirling Flow ◽  
Flow Conditions ◽  
Solid Body Rotation ◽  
Swirl Generator ◽  
Swirl Flows ◽  
Swirl Intensity ◽  
Pipe Inlet ◽  
Mathematical Relations ◽  
Intensity Decay

In this research the trend of swirl decay and factors influencing the turbulent swirl flows have been investigated in a fixed pipe. In this regard, turbulent swirling decay flow with solid body rotation has been numerically surveyed using different flow conditions at the pipe inlet. The numerical results have been validated and compared with the existing mathematical relations having satisfactory agreement. Results show that the swirl intensity decay rate has strong dependency on the Reynolds number. On this basis, correlations have been proposed which improves predictions of swirl intensity decay rate at upstream regions and those with high swirl intensity. In addition, analyses have been made to demonstrate that the previously developed correlations for predicting swirl intensity decay rate, agree with those provided in this study only for regions far enough down stream having the low swirl intensity. This implies that the swirl intensity decay rate should be a function of the type of swirl generator at the inlet.

Analytical investigation of boundary layer growth and swirl intensity decay rate in a pipe

2010 ◽  
Vol 81 (4) ◽  
pp. 489-501 ◽  
Author(s):  
Reza Maddahian ◽  
Azadeh Kebriaee ◽  
Bijan Farhanieh ◽  
Bahar Firoozabadi
Keyword(s):  
Boundary Layer ◽  
Decay Rate ◽  
Analytical Investigation ◽  
Layer Growth ◽  
Swirl Intensity ◽  
Boundary Layer Growth ◽  
Intensity Decay

Performance characteristics of flow in annular diffuser using CFD

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hardial Singh ◽  
Bharat Bhushan Arora
Keyword(s):  
Swirling Flow ◽  
Flow Behavior ◽  
Pressure Recovery ◽  
Ansys Fluent ◽  
Pressure Loss Coefficient ◽  
Swirl Angle ◽  
Swirl Intensity ◽  
Annular Diffuser ◽  
Inlet Swirl ◽  
Total Pressure Loss Coefficient

Abstract An annular diffuser is a critical component of the turbomachinery, and its prime function is to reduce the flow velocity. The current work is carried to study the effect of four different geometrical designs of an annular diffuser using the ANSYS Fluent. The numerical simulations were carried out to examine the effect of fully developed turbulent swirling and non-swirling flow. The flow behavior of the annular diffuser is analyzed at Reynolds number 2.5 × 105. The simulated results reveal pressure recovery improvement at the casing wall with adequate swirl intensity at the diffuser inlet. Swirl intensity suppresses the flow separation on the casing and moves the flow from the hub wall to the casing wall of the annulus region. The results also show that the Equal Hub and Diverging Casing (EHDC) annular diffuser in comparison to other diffusers has a higher static pressure recovery (C p  = 0.76) and a lower total pressure loss coefficient of (C L  = 0.12) at a 17° swirl angle.

scholarly journals Simulation Investigation on the Flow and Mixing in Ducts of the Rotary Energy Recovery Device

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Kai Liu ◽  
Lixing Zheng
Keyword(s):  
Fluid Dynamics ◽  
Energy Recovery ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Working Process ◽  
Mixing Rate ◽  
Typical Structure ◽  
Mixing Performance ◽  
Swirl Intensity ◽  
High Turbulence

The rotary energy recovery device (RERD) is widely equipped in desalination to reduce the system energy consumption. In this study, the fluid dynamics and mixing performance of a typical structure RERD and a visualization apparatus of a RERD (V-RERD) had been compared by simulation. The effects of rotating components on fluid dynamics and mixing had been researched. Simulation results indicated that a swirling flow can be observed from flow fields in the device duct. In the RERD case, the swirling flow changed its rotating direction in the center of the duct, while in the V-RERD case, its rotating direction was unchanged. Then, a swirling number Sn was applied to characterize the degree of swirl intensity, and its formation mechanism in RERD had been discussed. In addition, the Q criterion was adopted to visualize the three-dimensional flow structures and identify vortex structures in the duct. The evolution of vortices in the working process had been investigated. It was found that vortices significantly affected the mixing performance, and the detached vortex could lead to high turbulence and mixing in the duct. Suppressing the vortex shedding may reduce the flow turbulence and gain a lower volumetric mixing rate.

scholarly journals NUMERICAL ANALYSIS OF SWIRL INTENSITY IN TURBULENT SWIRLING PIPE FLOWS

2016 ◽  
Vol 78 (5-10) ◽  
Author(s):  
Bahbibi Rahmatullah ◽  
Khairul Fikri Tamrin ◽  
Nadeem Ahmed Sheikh
Keyword(s):  
Turbulent Flow ◽  
Swirling Flow ◽  
Reynolds Stress Model ◽  
Swirling Flows ◽  
Complex Flow ◽  
Cfd Simulations ◽  
Swirl Intensity ◽  
Computational Fluid Dynamics Cfd ◽  
Computational Resources ◽  
And Control

Swirling flows are often observed in nature such as weather systems, cyclones and tornados. A number of applications use swirling nature of flow for enhanced mixing, heat transport and other transport phenomena. Naturally occurring swirls as well as induced swirls are often usually turbulent in nature. Understanding the flow physics of turbulent swirling flow is important for better understanding and control of processes involving swirling flows. With the increase of computational resources and advancements in turbulent flow modelling, it is now possible to simulate highly complex flow structures. Here turbulent swirling flow induced by guide vanes is studied using Computational Fluid Dynamics (CFD) simulations in a two-dimensional axisymmetric channel. The results for the variation of velocity components are compared with the work of an earlier research. The results are initially compared for the evaluation of best discretisation scheme. It was observed that the second-order and third-order schemes produced similar results. To simulate the turbulent flow two equations (k-ε) model and the five equations Reynolds Stress Model (RSM) are used. The comparison of both models with higher order discretisation schemes shows that the standard k-ε model is incapable of predicting the main features of the flow whilst RSM yields result close to the experimental data.

Effect of a protective layer on the lifetime and output radiation intensity decay rate of quartz low-pressure gas discharge lamps

2006 ◽  
Vol 32 (1) ◽  
pp. 42-44 ◽  
Author(s):  
A. I. Vasils’ev ◽  
L. M. Vasilyak ◽  
S. V. Kostyuchenko ◽  
N. N. Kudryavtsev ◽  
M. E. Kuzs’menko ◽  
...  
Keyword(s):  
Decay Rate ◽  
Radiation Intensity ◽  
Protective Layer ◽  
Low Pressure ◽  
Gas Discharge ◽  
Output Radiation ◽  
Intensity Decay

scholarly journals 307 Influence of Swirl Intensity on Flow and Mass Transfer behind an Orifice in Curved Swirling Flow

2014 ◽  
Vol 2014.51 (0) ◽  
pp. _307-1_-_307-2_
Author(s):  
Nobuaki KANATANI ◽  
Tsuyoshi TAKANO ◽  
Takayuki YAMAGATA ◽  
Shou NISHIMIYA ◽  
Kazuya UTIYAMA ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Swirling Flow ◽  
Swirl Intensity

scholarly journals Determination of order in linear fractional differential equations

2018 ◽  
Vol 21 (4) ◽  
pp. 937-948 ◽  
Author(s):  
Mirko D’Ovidio ◽  
Paola Loreti ◽  
Alireza Momenzadeh ◽  
Sima Sarv Ahrab
Keyword(s):  
Differential Equations ◽  
Asymptotic Behaviour ◽  
Decay Rate ◽  
Fractional Differential Equations ◽  
Fractional Derivatives ◽  
Numerical Investigations ◽  
Fractional Differential ◽  
Linear Fractional Differential Equations

Abstract The order of fractional differential equations (FDEs) has been proved to be of great importance in an accurate simulation of the system under study. In this paper, the orders of some classes of linear FDEs are determined by using the asymptotic behaviour of their solutions. Specifically, it is demonstrated that the decay rate of the solutions is influenced by the order of fractional derivatives. Numerical investigations are conducted into the proven formulas.

Sign in / Sign up

Export Citation Format

Share Document