Friction factor in micropipe gas flow under laminar, transition and turbulent flow regime

This paper presents experimental investigations on turbulent gas flow characteristics of nitrogen gas through a micro-channel. The micro-channels were etched into silicon wafers, capped with glass, and their hydraulic diameter is 147.76 micro meters. The micro-channel was designed with a main flow channel and seven side channels, which lead to the pressure transducers. The stagnation pressure was designated in such a way that the flow is in turbulent flow regime. The outlet of the channel faced to the atmosphere. The pressures of the main channel at seven locations were measured by gauge pressure transducers to determine local values of Mach number. And the pressure differences of each pressure ports were measured by differential pressure transducers to obtain the pressure losses precisely. The pressure distribution of turbulent gas flow through a micro-channel falls steeply and Mach number increases near the outlet with increasing the inlet pressure due to flow acceleration. Both Darcy friction factor and Fanning friction factor were obtained for turbulent flow. The result shows that the obtained both friction factors were evaluated as a function of Reynolds number on the Moody chart. The values of Darcy friction factors differ from Blasius correlation for turbulent flow regime due to the compressibility effects, however the values of Fanning friction factors coincide with Blasius correlation.

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Convective Heat Transfer Characteristics of Low Concentration CuO-Water Nanofluids in the Turbulent Flow Regime Based on an Artificial Intelligence Models

Proceedings of the 15th International Heat Transfer Conference ◽

10.1615/ihtc15.fcv.008461 ◽

2014 ◽

Author(s):

Mehdi Mehrabi ◽

Mohsen Sharifpur ◽

Josua P. Meyer

Keyword(s):

Heat Transfer ◽

Artificial Intelligence ◽

Turbulent Flow ◽

Convective Heat Transfer ◽

Flow Regime ◽

Convective Heat ◽

Heat Transfer Characteristics ◽

Turbulent Flow Regime ◽

Intelligence Models ◽

Artificial Intelligence Models

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Thermal performance analysis of plate fin arrays with hexagonal perforations under turbulent flow regime

10.1063/1.5115847 ◽

2019 ◽

Author(s):

Imtiaz Taimoor ◽

Md Lutfor Rahman ◽

Nazneen Sultana Aankhy ◽

Muzahid Bin Khalid

Keyword(s):

Performance Analysis ◽

Turbulent Flow ◽

Flow Regime ◽

Thermal Performance ◽

Turbulent Flow Regime

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Numerical investigation on the thermohydraulic performance of a shell-and-double concentric tube heat exchanger using nanofluid under the turbulent flow regime

Numerical Heat Transfer Part A Applications ◽

10.1080/10407782.2016.1264736 ◽

2017 ◽

Vol 71 (2) ◽

pp. 215-231 ◽

Cited By ~ 9

Author(s):

S. M. Shahril ◽

G. A. Quadir ◽

N. A. M. Amin ◽

Irfan Anjum Badruddin

Keyword(s):

Heat Exchanger ◽

Turbulent Flow ◽

Numerical Investigation ◽

Flow Regime ◽

Tube Heat Exchanger ◽

Turbulent Flow Regime

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Loss Characteristics of Orifices and Nozzles

Journal of Fluids Engineering ◽

10.1115/1.3448670 ◽

1978 ◽

Vol 100 (3) ◽

pp. 299-307 ◽

Cited By ~ 20

Author(s):

S. H. Alvi ◽

K. Sridharan ◽

N. S. Lakshmana Rao

Keyword(s):

Reynolds Number ◽

Turbulent Flow ◽

Flow Regime ◽

Discharge Coefficient ◽

Critical Reynolds Number ◽

Reynolds Numbers ◽

Center Line ◽

Laminar Regime ◽

Variation Of Parameters ◽

Turbulent Flow Regime

Loss characteristics of sharp-edged orifices, quadrant-edged orifices for varying edge radii, and nozzles are studied for Reynolds numbers less than 10,000 for β ratios from 0.2 to 0.8. The results may be reliably extrapolated to higher Reynolds numbers. Presentation of losses as a percentage of meter pressure differential shows that the flow can be identified into fully laminar regime, critical Reynolds number regime, relaminarization regime, and turbulent flow regime. An integrated picture of variation of parameters such as discharge coefficient, loss coefficient, settling length, pressure recovery length, and center line velocity confirms this classification.

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Investigation of Flow Dynamics Over Transitional-Type Microcavity

Journal of Fluids Engineering ◽

10.1115/1.4039159 ◽

2018 ◽

Vol 140 (7) ◽

Cited By ~ 1

Author(s):

Paulius Vilkinis ◽

Nerijus Pedišius ◽

Mantas Valantinavičius

Keyword(s):

Turbulent Flow ◽

Flow Regime ◽

Recirculation Zone ◽

Transitional Flow ◽

Navier Stokes ◽

Flow Topology ◽

Rans Equations ◽

Recirculation Flow ◽

Turbulent Flow Regime ◽

Transitional Type

Flow over a transitional-type cavity in microchannels is studied using a microparticle image velocimetry system (μPIV) and commercially available computational fluid dynamics (CFD) software in laminar, transitional, and turbulent flow regimes. According to experimental results, in the transitional-type cavity (L/h1 = 10) and under laminar flow in the channel, the recirculation zone behind the backward-facing step stretches linearly with ReDh until the reattachment point reaches the middle of the cavity at xr/L = (0.5 to 0.6). With further increase in ReDh, the forward-facing step lifts the reattaching flow from the bottom of the cavity and stagnant recirculation flow fills the entire space of the cavity. Flow reattachment to the bottom of the cavity is again observed only after transition to the turbulent flow regime in the channel. Reynolds-averaged Navier–Stokes (RANS) equations and large eddy simulation (LES) results revealed changes in vortex topology, with the flow regime changing from laminar to turbulent. During the turbulent flow regime in the recirculation zone, periodically recurring vortex systems are formed. Experimental and computational results have a good qualitative agreement regarding the changes in the flow topology. However, the results of numerical simulations based on RANS equations and the Reynolds-stress-baseline turbulence model (RSM-BSL), show that computed reattachment length values overestimate the experimentally obtained values. The RSM-BSL model underestimates the turbulent kinetic energy intensity, generated by flow separation phenomena, on the stage of transitional flow regime.

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