CFD Study of Pitch Variations On Helically Coiled Pipe in Laminar Flow Region

2020 ◽  
Author(s):  
Anwer Faraj ◽  
Itimad D J Azzawi ◽  
Samir Ghazi Yahya ◽  
Amer Al-damook
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Laminar Flow ◽  
Friction Factor ◽  
Flow Structure ◽  
Flow Region ◽  
Alternative Solution ◽  
Experimental Investigations ◽  
Coil Diameter ◽  
Computational Fluid Dynamics Cfd

Abstract Experimental investigations of the flows inside helically coiled pipe are difficult and may also be expensive, particularly for small diameters. Computational fluid dynamics (CFD) packages, which can easily construct the geometry and change the dimensions with 100% of accuracy, provide an alternative solution for the experimental difficulties and uncertainties. Therefore, a computational fluid dynamics (CFD) study was conducted to analyse the flow structure and the effect of varying the coil pitch on the coil friction factor, through utilising different models' configurations. Two coils were tested, all of them sharing the same pipe and coil diameter: 0.005m and 0.04m respectively. Pitch variations began with 0.01 and 0.05 m for the first, second model respectively. In this study, the velocity was analysed, and the effects of this reduction on coil friction factor were also examined using laminar flow. The results were validated by Ito's equation for the laminar flow.

Flow over a glider canopy

2014 ◽  
Vol 118 (1204) ◽  
pp. 669-682
Author(s):  
A. S. Jonker ◽  
J. J. Bosman ◽  
E. H. Mathews ◽  
L. Liebenberg
Keyword(s):  
Fluid Dynamics ◽  
Boundary Layer ◽  
Computational Fluid Dynamics ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Aerodynamic Drag ◽  
Canopy Gap ◽  
Experimental Investigations ◽  
Front Part ◽  
Gap Width

Abstract In order to minimise drag, the front part of most modern glider fuselages is shaped so that laminar flow is preserved to a position close to the wing-to-fuselage junction. Experimental investigations on a full-scale JS1 competition glider however revealed that the laminar boundary layer in fact trips to turbulent flow at the fuselage-to-canopy junction position, increasing drag. This is possibly due to ventilation air leaking from the cockpit to the fuselage surface through the canopy seal, or that the gap is merely too large and therefore trips the boundary layer to turbulent flow. The effect of air leaking from the fuselage-to-canopy gap as well as the size of the gap was thus investigated with the use of computational fluid dynamics. It was found that if air was leaking through this gap the boundary layer would be tripped from laminar to turbulent flow. It was also found that the width of the canopy-to-fuselage gap plays a significant role in the preservation of laminar flow. If the gap is less than 1mm wide, the attached boundary layer is able to negotiate the gap without being tripped to turbulent flow, while if the gap is 3mm and wider, it will be tripped from laminar to turbulent flow. The work shows that aerodynamic drag on a glider can be significantly minimised by completely sealing the fuselage-to-canopy gap and by ensuring a seal gap-width of less than 1mm.

scholarly journals Comparative performance analysis of innovative separation chamber configurations: Numerical and experimental investigations

2021 ◽  
Vol 19 (2) ◽  
pp. e0206
Author(s):  
Mansour Zobeiri ◽  
Vahid Rostampour ◽  
Adel Rezvanivand-Fanaei ◽  
Ali M. Nikbakht
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Similar Case ◽  
Separation Efficiency ◽  
Critical Issue ◽  
Experimental Investigations ◽  
Comparative Performance ◽  
Separation Chamber ◽  
Computational Fluid Dynamics Cfd ◽  
Series Type

Aim of study: Novel configurations of separation chamber are proposed to resolve the critical issue of separation in agro-industrial equipment.Area of study: Dept. of Mechanical and Biosystems Engineering, Urmia, IranMaterial and methods: Precise and instrumented experimentation has been conducted to calibrate the computational fluid dynamics (CFD) methodology in the modeling and simulating chickpea pod separation. Mechanisms were selected based on optimizing separation efficiency, relative purification and required airflow as a criterion for energy consumption.Main results: Applying a guiding blade and suction fans may potentially increase the separation efficiency while reducing the relative purification and required airflow. The highest separation efficiency (95%), the lowest required airflow (545 m³/h) and the lowest pressure drop (16.3 Pa), were obtained by such configuration. Furthermore, the highest relative purification of 90% was achieved when the mechanism was free of blade and fans.Research highlights: To integrate the advantages of the above-mentioned configurations, a series-type assembling them is proposed to preserve the separation efficiency and relative purification at the highest level, meanwhile reducing the required airflow. Also, 15% enhancement in the separation efficiency and 302.8 m³/h reductions in the airflow were found as a crucial finding. The high correlation of experimental and theoretical CFD results is the key point to motivate the researchers for extension of similar case projects.

Assessment on Effects of Under-Relaxation Factors on 2D Incompressible Laminar Flow over a Backward-Facing Step (BFS)

2012 ◽  
Vol 225 ◽  
pp. 55-59
Author(s):  
Yogeswaran Sinnasamy ◽  
Noor Arbiah Yahaya ◽  
Shahnor Basri ◽  
Abdul Aziz Jaafar ◽  
Azmin Shakrine Mohd Rafie
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Laminar Flow ◽  
Computational Studies ◽  
Backward Facing Step ◽  
Relaxation Factor ◽  
2D Simulation ◽  
Computational Fluid Dynamics Cfd ◽  
Relaxation Factors ◽  
Error Percentage

In this paper, the effects of changing under-relaxation factors for different variables on the numerical solution of 2D incompressible laminar flow over a backward-facing step (BFS) are studied using PHOENICS commercial Computational Fluid Dynamics (CFD) software. This is conducted by changing under-relaxation factors for velocities and pressure during the 2D simulation. Ten different batches of under-relaxation factor for pressure ranging from 0.1 to 1.0 were used while the values of under-relaxation factor for velocities were manipulated between 0.1 and 1.0. For each batch of the computation, the error percentage of pressure and velocities were obtained. Based on this work, it is found that the recommended values of under-relaxation factor for pressure to achieve lower error percentage are between 0.6 and 0.8. Based on findings of the study, the appropriate values of under-relaxation factor for pressure and velocities can be selected to achieve the levels of error percentage permitted for computational studies.

Using Experimental Fluid Dynamics and Computational Fluid Dynamics for Evaluating Periodic Mixing

2018 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Leonard F. Pease ◽  
Kurtis P. Recknagle ◽  
Carl W. Enderlin ◽  
Michael J. Minette
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
System Performance ◽  
Experimental Investigations ◽  
Cfd Simulations ◽  
Mixing Processes ◽  
Experimental Fluid Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Fluid ◽  
Pulse Jet

Periodic mixing using pulse jet mixers is being developed and applied for processing unique slurries of radioactive waste that depending upon the slurry properties may possess either Newtonian or non-Newtonian characteristics. To investigate the performance of these mixing systems, scaled experimental fluid dynamics (EFD) experiments have been conducted and in addition, for certain investigations, computational fluid dynamics (CFD) simulations have been applied. The purpose of this paper is to describe the periodic mixing processes, elaborate regarding the types of scaled experiments that were conducted, and present examples of computational investigations conducted to further define the mixing system performance. The experimental investigations showed the ability to track visual metrics such as cloud height and cavern size. The computational investigations demonstrated the ability to model full-scale experiments with Newtonian slurries.

Sign in / Sign up

Export Citation Format

Share Document