scholarly journals Estimation of Minor Loss Coefficient Associated with Fitting of Venturimeter in a Pipe System

2019 ◽  
Vol 9 (2S2) ◽  
pp. 4-7
Keyword(s):  
Loss Coefficient ◽  
Mathematical Equation ◽  
Pipe Fitting ◽  
Pipe System ◽  
Reynold’S Number ◽  
Minor Losses

Quantification of minor losses associated with a pipe fitting and regular updating is necessary for ensuring the sustainability of the system. In this study, based on simple lab based experiments, the minor loss coefficient associated with a venturimeter fitted in a pipe system is estimated. It is seen that the loss coefficient varies inversely with the increase in the Reynold’s number and can be depicted with a simple mathematical equation.

Numerical Investigation of a Globe Control Valve and Estimating its Loss Coefficient at Different Opening States

2021 ◽  
Author(s):  
Saber Rezaey
Keyword(s):  
Pressure Ratio ◽  
Functional Relation ◽  
Control Valve ◽  
Head Loss ◽  
Loss Coefficient ◽  
Rate Of Change ◽  
Minor Losses ◽  
Pressure Changes ◽  
Globe Control Valve ◽  
Oil Gas

One of the most important components of fluid transmission systems is a control valve located in the pipelines of oil, gas, etc. The primary purpose of this valve is to control the rate of fluid flow passing through it under pressure changes and the most important issue is to investigate the flow’s characteristics in order to achieve a proper geometry to control the flow rate and pressure as desired. The valves used in pipelines add to the overall head loss of the system. Therefore, valves with proper geometry can reduce these minor losses and finally decrease total energy losses. In this paper, a globe control valve is modeled and then numerically investigated to extract its functional relation, which relates pressure ratio to inlet Reynolds number, and estimate its loss coefficient at the valve’s different opening states which have not been addressed completely before and can be beneficial for the selection and usage of globe valves under certain conditions. According to the results, it is found that pressure ratio and loss coefficient are functions of inlet velocity and the valve’s opening state’s percentage, which are directly related to the valve’s geometry. When the valve opens, the rate of change in pressure ratio and loss coefficient are very sharp. Gradually, this rate decreases and the results tend to the final value at the valve’s fully opened state.

scholarly journals Numerical simulation of minor losses coefficient on the example of elbows

2018 ◽  
Vol 180 ◽  
pp. 02093
Author(s):  
Smyk Emil ◽  
Mrozik Dariusz ◽  
Olszewski Łukasz ◽  
Peszyński Kazimierz
Keyword(s):  
Numerical Simulation ◽  
Numerical Methods ◽  
Numerical Method ◽  
Cross Section ◽  
Analytical Methods ◽  
Circular Cross Section ◽  
Experimental Methods ◽  
Loss Coefficient ◽  
Complicated Problem ◽  
Minor Losses

Determining of minor losses coefficient is very complicated problem. Analytical methods are often very difficult and experimental methods are very expensive and time-consuming. Consequently, the use of numerical methods seems to be a good solution, but there are no publications describing this issue. Therefore, the paper is describing the numerical method of determining the minor loss coefficient ξ on the example of elbows with circular cross-section.

Contraction/Expansion Effects in 90° Miter Bends in Rectangular Xurographic Microchannels

2011 ◽  
Author(s):  
Lam Nguyen ◽  
John Elsnab ◽  
Tim Ameel
Keyword(s):  
Reynolds Number ◽  
Critical Reynolds Number ◽  
Area Ratio ◽  
Loss Coefficient ◽  
Sidewall Roughness ◽  
Cross Sectional ◽  
Loss Coefficients ◽  
Minor Losses ◽  
High Reynolds ◽  
Reported Data

Xurography is an inexpensive rapid prototyping technology for the development of microfluidic systems. Imprecision in the xurographic tape cutting process can result in undesired changes in channel dimensions near features that require a change in cutting direction, such as 90° miter bends. An experimental study of water flow in rectangular xurographic microchannels incorporating 90° miter bends with different channel widths in each leg is reported. A set of twelve microchannels, with channel depth approximately 105 micrometers and aspect ratio ranging from 0.071 to 0.435, were fabricated from double-sided adhesive Kapton® polyimide tape and two rectangular glass plates. The channels were reinforced with a mechanical clamping system, enabling high Reynolds number, Re, flows (up to Re = 3200) where Re was based upon hydraulic diameter and average velocity. Reported data include friction factor and critical Reynolds number for straight microchannels and loss coefficients for flow through 90° miter bends that contain either a contraction or expansion with cross-sectional area ratios of 0.5, 0.333 and 0.2. The critical Reynolds number, Recr, ranged from 1750 to 2300 and was found to be dependent on channel defects such as sidewall roughness, adhesive droplets, and corner imperfections. Loss coefficients through 90° miter bends with expansion decrease rapidly for Re < Recr. At the transition, the loss coefficient suddenly drops and approaches an asymptotic value for Re > Recr. For 90° miter bends with contractions, loss coefficients gradually decrease with increasing Re for 150 < Re < 1400. In addition, the loss coefficient decreases with decreasing area ratio through the contraction or expansion. The minor loss coefficient data were found to be dependent on Reynolds numbers and area ratio of contraction/expansion at the bend. The results suggest that the effect of the contraction/expansion was the dominant mechanism for minor losses in the 90° miter bend.

The Investigation of Minor Losses in T-Pipe Flow

2013 ◽  
Author(s):  
Dajie Sun ◽  
Donghui Zhang ◽  
Wenjun Hu ◽  
Lixia Ren
Keyword(s):  
Pressure Drop ◽  
Reference Data ◽  
Liquid Sodium ◽  
Empirical Formulas ◽  
Control Rod ◽  
Pipe System ◽  
Pressure Losses ◽  
Flow Through ◽  
Minor Losses ◽  
Reasonable Model

It is now known explicitly how to calculate the pressure losses due to a developed flow in a pipe. As for pipe system, for simplicity, the minor losses caused by valves, elbows, enlargements, inlets, outlets, and other fittings was considered to be ignorable when compared with the frictional losses. However, actually, this is not always the case. In the work designing the safety rods for next generation of fast reactor, the inner structure which makes a large part of contribution to the pressure drop when the liquid sodium flow through them, should be considered carefully. In this case, the pressure losses due to T-joint need to be calculated. And unfortunately, empirical formulas couldn’t be found through the combination of survey and the huge quantity of reference data to solve the problem perfectly. In this paper, several simplified models are proposed to calculate to minor loss in T-pipe, which could be implied to the calculation of pressure drop of safety nod, and by comparing their feather, the most reasonable model is found. It has been found that even different models give different results of minor losses, the total pressure drop of the control rod, however, deviates no more than five percent.

Minor Losses Due to Flow Through a Rounded Sudden Expansion

2003 ◽  
Author(s):  
Barton L. Smith
Keyword(s):  
Reynolds Number ◽  
Kinetic Energy ◽  
Steady Flow ◽  
Loss Coefficient ◽  
Pressure Recovery ◽  
Sudden Expansion ◽  
Flow Energy ◽  
Uniform Velocity ◽  
Flow Through ◽  
Minor Losses

Experiments on steady flow through a nominally 2-D exit geometry with rounded edges are presented. The minor loss coefficient, K, can be greater than unity for sudden expansions with non-uniform velocity profiles. Pressure recovery due to deceleration of the exiting flow before it detaches results in conversion of kinetic energy to flow energy and a reduced the value of K. It is shown that K is a function of the dimensionless edge radius and the Reynolds number. Substantial pressure recovery is reported at large Re for r/h < 1.

Sign in / Sign up

Export Citation Format

Share Document