Numerical Investigation on the Friction Factor Estimation for Laminar and Turbulent Flow in Smooth Pipe

2021 ◽  
pp. 489-496
Author(s):  
S. A. Mashalkar ◽  
S. P. Nagdewe
Keyword(s):  
Turbulent Flow ◽  
Friction Factor ◽  
Numerical Investigation ◽  
Laminar And Turbulent Flow ◽  
Smooth Pipe ◽  
Factor Estimation

Numerical investigation of friction laws for laminar and turbulent flow in undulated channels

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ali Cemal Benim ◽  
Sai Bhagavan Maddala
Keyword(s):  
Laminar Flow ◽  
Turbulent Flow ◽  
Numerical Investigation ◽  
Focal Point ◽  
Hydraulic Diameter ◽  
Maximum Deviation ◽  
Content Type ◽  
Friction Laws ◽  
Numerical Predictions ◽  
Laminar And Turbulent Flow

Purpose The purpose of this paper is the numerical investigation of the friction laws for incompressible flow in undulated channels, with emphasis on the applicability of the hydraulic diameter concept. A focal point of the study is the derivation of correlations to increase the accuracy of the hydraulic diameter approach. Design/methodology/approach Calculations are performed for laminar and turbulent flow, for Reynolds number ranges between 10–2,000 and 5,000–100,000. For turbulent flow, the shear stress transport (SST) model is used. A simple, sawtooth-like undulation shape is considered, where the channel geometry can be described by means of three length parameters. Letting each to take three values, totally 27 geometries are analyzed. Findings It is observed that the hydraulic diameter concept applied via analytical or empirical expressions to obtain friction coefficients does not lead to accurate results. For laminar flow, the maximum deviations of analytical values from predicted are about 70%, while 20% deviation is observed on average. For turbulent flow, deviations of Blasius correlation from predicted ones are smaller, but still remarkable with about 20% for maximum deviation and about 10% on average. Originality/value Applicability of the hydraulic diameter concept to undulated channels was not computationally explored. A further original ingredient of the work is the derivation of correlations that lead to improved accuracy in calculating the friction coefficient using hydraulic diameter. For laminar flow, the maximum and average deviations of present correlations from numerical predictions are below 5% and 2%, respectively. For turbulent flow, these numbers turn out to be approximately 12% for the maximum deviation and about 2% for the average.

scholarly journals DERIVING THE SEMI-EMPIRICAL FORMULA TO COMPUTE THE FRICTION FACTOR λ FOR TURBULENT FLOW IN PIPE

2010 ◽  
Vol 13 (2) ◽  
pp. 48-58
Author(s):  
Duc Van Le
Keyword(s):  
Turbulent Flow ◽  
Friction Factor ◽  
Research Result ◽  
Shear Velocity ◽  
Point Of View ◽  
Mixing Length ◽  
Smooth Pipe ◽  
Wetted Area ◽  
Set Up ◽  
Mixing Length Theory

Based on law of shear stress in turbulent flow. Prandd's mixing length theory, and Bakhmeteflfs point of view on "wall velocity", turbulent velocity distribution u on wetted area can be derived for smooth pipe and complete turbulence, rough pipe. Discharge Q and average velocity y are obtained, after the integration, Q= ∫∫wu.dw is done. Relying on the properties of uniform flow, relationship between V, friction factor λ, and shear velocity u is set up. After eliminating u*. velocity V is obtained as a function of Reynolds number Re or relative roughness e/D. Finally, the value of friction factor z can be derived as a function of Re or e/D for the two above-mentioned cases. These formations of z formulas are almost same as the experimental ones introduced by Nikuradse with minor deviations in the factors and their relative errors do not exceed 1% for smooth pipe, and 2% for complete turbulence, rough pipe. Through this research result, the rightness of Prandtl's mixing length theory is almost asserted.

scholarly journals KARAKTERISTIK TERMAL HIDRODINAMIK UNTUK ALIRAN LAMINAR DAN TURBULEN DI DALAM PIPA DENGAN BERBAGAI BENTUK SISIPAN PLAT BERGALUR

ROTASI ◽  
2015 ◽  
Vol 17 (4) ◽  
pp. 182
Author(s):  
Syaiful Syaiful ◽  
Faza Dzulhimam
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Three Dimensional ◽  
Working Fluid ◽  
Hydrodynamic Characteristics ◽  
Transfer Enhancement ◽  
Three Dimensional Flow ◽  
Laminar And Turbulent Flow ◽  
Heat Transfer Improvement

The purpose of this study is to investigate the thermal and hydrodynamic characteristics of air flowing in tubes with various inserts of grooved plate. Inserts of grooved plate with a variety of attack angles (a = 0°, 45° and 90°) has been studied in laminar and turbulent flow. Plate inserts are installed inside the tube intended to improve the heat transfer due to the mixing of the fluid. Numerical simulation of three-dimensional flow set as a model in the direction of fluid flow. The working fluid in the tube is cold, whereas hot wall temperature is kept constant. The results showed that the grooved plate inserts increases the heat transfer in the tube. For laminar flow, the highest heat transfer enhancement is obtained at the grooved plate inserts α = 45° i.e. from 4.46 to 20.34% with an increase in friction factor of 172.19 to 204.36%. As for the turbulent flow, the highest heat transfer improvement is found in a grooved plate inserts with α = 45° i.e. from 38.67 to 56.1% with an increase in friction factor of 183.5 to 262.29%.

scholarly journals Optimization of Conical Hydrostatic Bearing for Minimum Friction

1972 ◽  
Vol 94 (2) ◽  
pp. 136-142 ◽  
Author(s):  
L. J. Nypan ◽  
B. J. Hamrock ◽  
H. W. Scibbe ◽  
W. J. Anderson
Keyword(s):  
Laminar Flow ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Turbulent Flows ◽  
Flow Rate ◽  
Load Capacity ◽  
Friction Torque ◽  
Radius Ratio ◽  
Hydrostatic Bearing ◽  
Laminar And Turbulent Flow

Equations for the flow rate, load capacity, and friction torque for a conical hydrostatic bearing were developed. These equations were solved by a digital computer program to determine bearing configurations for minimum friction torque. Design curves are presented that show optimal bearing dimensions for minimum friction torque as a function of dimensionless flow rate for a range of dimensionless load capacity. Results are shown for both laminar and turbulent flow conditions. The results indicate the hydrostatic pocket friction is a significant portion of the total friction torque. However, the bearing dimensions for a minimum friction design are affected very little by inclusion of pocket friction in the analysis. For laminar flow the values of the outerland radius ratio X3 and outer bearing radius ratio X4 did not change significantly with increasing friction factor. For turbulent flow, the outer bearing radius ratio X4 did not change with increasing friction factor; therefore, the value determined for X4 in the laminar flow case is valid for all turbulent flows.

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