ANALYSIS OF OUTCOMES OF THE FRICTIONAL PRESSURE DROP PREDICTION USING DIFFERENT DATA SOURCE

2016 ◽  
Vol 78 (10-2) ◽  
Author(s):  
Qais Abid Yousif ◽  
Normah Mohd-Ghazali ◽  
Agus Sunjarianto Pamitran
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Friction Factor ◽  
Pipe Diameter ◽  
Lower Percentage ◽  
Pipe Material ◽  
Pipe Length ◽  
Frictional Pressure Drop ◽  
Blasius Equation ◽  
Data Source

Predictions of the frictional pressure drop using friction factor correlations that have been developed based on past experimental data have always been found to disagree with recent experimental data. Thus, new correlations are continuously being developed to generalize their applications across refrigerants and flow regimes. The friction factor is dependent on the Reynolds number and relative roughness, therefore consequently depends on the applied equation and fluid data. This research shows the outcome of the analysis of the frictional pressure drop prediction when different data source as well as different friction factor equations for smooth and rough pipes are utilized. The R-22 data used for comparison are experimental data from a past report, NIST (Standard Reference Database), and experimental data from University of Indonesia. The used e friction factor equations are Blasius and Fang et al. (2011) in smooth and rough pipe respectively. The mass flux is ranging from 200 to 600 kg/m2s and vapor quality from 0.0001 to 0.5, the latter of which is assumed constant along the pipe length of 2000 mm at the saturation temperature of 10°C. The pipe material is stainless steel with an absolute roughness of 0.03 mm. The minimization of the friction factor and two-phase flow frictional pressure drop is achieved by applying Genetic Algorithm (GA). The comparisons reveal that the differences are an indication of the appropriate data source necessary so that the frictional pressure drop can be accurately predicted. The results showed that in 1.5 mm pipe diameter, the Blasius equation gives the lower percentage of differences in the range of 0.69 – 1.47 % when the data from NIST and UI are used. While the lower percentage of differences gives Fang et al. (2011) equation in the range of 1.47 – 2.61% when data from Pamitran et al. (2010) and UI are used. In the 3 mm inner diameter, also Blasius equation gives the lower percentage of differences in the range of 0.89 – 2.52% when the data from Pamitran et al. (2010) and UI are used. While Fang et al. (2011) gives the lower percentage of differences in the range of 1.56 – 1.33% when the data from Pamitran et al. (2010) and UI are used. The proposed method is predictable to raise the accuracy of the prediction and decrease the time of testing. The results are compared between each other’s for different data sources. For most situations, the percentage difference, as well as for laminar and turbulent flows are between 91 – 97% and 88 – 95% in 1.5 and 3 mm pipe diameter respectively.

Optimized Condition for Pairing of Different Friction Factor and Viscosity Equations for the Frictional Pressure Drop of R22 and R290

2019 ◽  
Vol 27 (04) ◽  
pp. 1950037
Author(s):  
Qais Abid Yousif ◽  
Normah Mohd-Ghazali ◽  
Agus Sunjarianto Pamitran ◽  
Yushazaziah Mohd-Yunos
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Friction Factor ◽  
Environmentally Friendly ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Multi Objective Genetic Algorithm ◽  
Percentage Difference ◽  
The Many ◽  
Small Channels

Accurate prediction of the friction factor and consequently the pressure drop of two-phase flow in small channels is still an issue. Many correlations exist for the determination of the viscosity and the friction factor that appear in the frictional pressure drop and their combination often determined the degree of disagreements between the experimental data and predicted outcomes. Demands for environmentally friendly refrigerants have further posed a challenge to find compatible alternatives with as good a performance as the current coolants. Despite the many available correlations developed to date, many more are studied in effort to reduce the discrepancies. This paper presents the outcomes of a study comparing the optimized conditions when three different viscosity equations are paired with eight different friction factor correlations to minimize the frictional pressure drop. The approach used multi-objective genetic algorithm (MOGA) to assist in selecting the best pairing. Comparison is then completed with available experimental data. The study showed that the Blasius friction factor paired with the Dukler viscosity produced the least percentage difference for R22, while when paired with the McAdams viscosity produced a lower difference for R290, an environmentally friendly refrigerant being considered to replace R22.

Analysis of Friction Factor of Two-Phase Flow in Helically Coiled Tubes

2021 ◽  
Author(s):  
Baihui Jiang ◽  
Zhiwei Zhou ◽  
Yu Ji
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Friction Factor ◽  
Single Phase ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Steam Generators ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Applicable Range

Abstract With compact structure and enhanced heat transfer capacity, helical-coiled once through steam generators (HTSGs) are widely used in the small modular reactors (SMRs). Nevertheless, the inside centrifugal forces make the flow more complicated, and increase the frictional pressure drop, which is closely related to the dual test of alternating thermal stress and flow instability. Therefore, the analysis of the friction factor in helically coiled tubes is significant to the efficient and safe operation of HTSGs. While the friction factor of single-phase flow in helically coiled tubes was fully studied and extensive correlations have been validated by a large amount of experimental data, the friction factor of two-phase flow still lacks feasible prediction due to its much more complexity. The existed correlations of two-phase flow in helically coiled tubes are mostly based on specified experimental parameters, so the applicable range is limited. Few scholars have tried to extend these correlations to broader applicability, but the trivial applicable range is unsuitable for program development or engineering design, which needs an accurate prediction of friction factor in a wider range. In this paper, existing frictional pressure drop correlations are investigated. The accuracy of single-phase frictional pressure drop correlations is verified through the comparison of calculation results. Since the known experimental data cannot cover a wide range of parameters, two assumptions are proposed, and the rationality is verified through the existing experimental data and calculation analysis. Based on the two assumptions and calculation, a set of calculation correlations for frictional pressure drop of two-phase flow in helically coiled tubes are proposed. The accuracy of this calculation model is validated by experimental data. The scope of application of this model is: D / d = 15–100, P = 0.12–6.3MPa, G = 200–1500kg / m2s, which is sufficient to support the design and operation of steam generators and the development of the simulation programs.

Evaluation of Two-Phase Frictional Pressure Drop Correlations Against Experimental Data

2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Wei Li ◽  
Kunrong Shen ◽  
Boren Zheng ◽  
Xiang Ma ◽  
S. A. Sherif ◽  
...  
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Mass Flow ◽  
Flow Model ◽  
Saturation Temperature ◽  
Separated Flow ◽  
Outer Diameter ◽  
Two Phase ◽  
Homogeneous Flow ◽  
Frictional Pressure Drop

Abstract Results are presented here from an experimental investigation on tube side two-phase characteristics that took place in four tested tubes—the 1EHT-1, 1EHT-2, 4LB, and smooth tubes. The equivalent outer diameter of the tube was 9.52 mm and the inner diameter was 8.32 mm. Condensation tests were conducted using refrigerant R410A at a saturation temperature of 318 K, over a mass flow range of 150–450 kg m−2 s−1, with inlet and outlet vapor qualities of 0.8 and 0.2, respectively. Evaporation tests were performed at a saturation temperature of 279 K, over a mass flow range of 150–380 kg m−2 s−1, with inlet and outlet vapor qualities of 0.2 and 0.8, respectively. Pressure drop data of the four tested tubes were collected to evaluate five identified prediction correlations based on the separated flow model and the homogeneous flow model. The separated flow approaches presented predictions with average MAEs of 24.9% and 16.4% for condensation and evaporation data, respectively, while the average MAEs of the homogeneous flow model were 31.6% and 43.4%, respectively. Almost all the identified correlations underestimated the frictional pressure drop of the 4LB tube with MAEs exceeding 30%. An earlier transition of different flow patterns was expected to occur in the EHT tubes while developing a new diabatic flow pattern map is needed for the 4LB tube. A new correlation was presented based on the two-phase multiplier Φ and the Martinelli parameter Xtt, which exhibited excellent predictive results for the experimental data.

Evaluation of Existing Frictional Pressure Drop Correlations During Condensation of R410A in Four Horizontal Tubes

2019 ◽  
Author(s):  
Kunrong Shen ◽  
Zhichuan Sun ◽  
Wei Li ◽  
Xiang Ma ◽  
Yan He ◽  
...  
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Flow Model ◽  
Saturation Temperature ◽  
Separated Flow ◽  
Smooth Tube ◽  
Outer Diameter ◽  
Homogeneous Flow ◽  
Frictional Pressure Drop ◽  
Horizontal Tubes

Abstract Results are presented here from an experimental investigation on tube side condensation characteristics that took place in four tested tubes — 1EHT-1, 1EHT-2, 4LB and a smooth tube. The equivalent outer diameter of the tubes was 9.52 mm and the inner diameter was 8.32 mm. Condensation tests were conducted using refrigerant R410A at a saturation temperature of 318K, over a mass flow range of 150–450 kgm−2s−1, with inlet and outlet vapor quality of 0.8 and 0.2, respectively. Pressure drop data of the four tested tubes were collected to evaluate five identified prediction correlations based on the separated flow model and the homogeneous flow model. For 1EHT-2 and the smooth tube, all the listed correlations manage to present predictions with the Mean Absolute Relative Deviation (MARD) less than 30%, while they underestimate the frictional pressure drop of the 4LB tube with MARD exceeding 40% averagely. Regarding the experimental data, it is found that the Muller-Steinhagen and Heck correlation presents the most accurate and stable prediction for the 4 tested tubes. The listed homogeneous flow correlations can provide acceptable predictions with MARD ranging from 25% to 40% under a few conditions, but their average predictive accuracies are inferior to that of the separated flow correlations. Consequently, the separated flow approach performs better than the homogeneous flow model in the prediction of frictional pressure drop for our experimental data.

Experimental Study on Resistance Characteristics in a 3 × 3 Rod Bundle

2014 ◽  
Author(s):  
Chaoxing Yan ◽  
Changqi Yan ◽  
Licheng Sun ◽  
Yang Wang
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Pressure Drop ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Local Resistance ◽  
Local Pressure ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Rod Bundle

Experimental study on resistance of air-water two-phase flow in a vertical 3 × 3 rod bundle was carried out under normal temperature and pressure. The rod diameter and pitch were 8 mm and 11 mm, respectively. The ranges of gas and liquid superficial velocity were 0.013∼3.763 m/s and 0.076∼1.792 m/s, respectively. The result indicated that the existing correlations for calculating frictional coefficient in the rod bundle and local resistance coefficient could not give favorable predictions on the single-phase experimental data. For the case of two-phase flow, eight correlations for calculating two-phase equivalent viscosity poorly predicted the frictional pressure drop, with the mean absolute errors around 60%. Meanwhile, the eight classical two-phase viscosity formulae were evaluated against the local pressure drop at spacer grid. It is shown that Dukler model predicted the experimental data well in the range of Rel<9000 while McAdams correlation was the best for Rel⩾9000. For all the experimental data, Dukler model provided the best prediction with MRE of 29.03%. Furthermore, approaches to calculate two-phase frictional pressure drop and local resistance were proposed by considering mass quality, two-phase Reynolds number and densities in homogenous flow model, resulting in a good agreement with the experimental data.

Frictional Pressure Drop in Micro-Channel

2004 ◽  
Author(s):  
Yasuo Koizumi ◽  
Hiroyasu Ohtake ◽  
Hiroki Takahashi ◽  
Yoshiaki Ohno
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Frictional Pressure Drop ◽  
Turbulent Transition ◽  
Friction Factors ◽  
Turbulent Flow Regime ◽  
Form Pressure ◽  
Laminar And Turbulent Flow ◽  
Flow Through

The friction characteristics of water in a sub-millimeter scale channel were investigated experimentally. The friction factors and the critical Reynolds number were measured using water flow through circular tubes with diameters of 0.5, 0.25 and 0.17 mm. The experimental results show that the measured friction factor for water agreed well with the conventional Poiseuille (λ = 64/Re) and Blasius (λ = 0.316 Re−0.25) equations in laminar and turbulent flow regime; the laminar-turbulent transition Reynolds number was approximately 2300 for diameter 0.5 mm. For diameter 0.25 mm, the friction factor evaluated by the form pressure drop also agreed well with the Poiseuille equation. For diameter 0.17 mm, the measured total friction factor was close to the Poiseuille prediction.

Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes

2006 ◽  
Author(s):  
Xia-Xin Cao ◽  
Chang-Qi Yan ◽  
Pu-Zhen Gao ◽  
Zhong-Ning Sun
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Single Phase ◽  
Experimental Studies ◽  
Frictional Coefficient ◽  
Bubble Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Rolling Condition ◽  
New Correlation

A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15mm, 25mm and 34.5mm respectively, the rolling angles of tubes could be set as 10° and 20°, and the rolling periods could be set as 5s, 10s and 15s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%.

Effect of Void Fraction on Pressure Drop in Upward Vertical Two-Phase Gas-Liquid Pipe Flow

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Clement C. Tang ◽  
Sanjib Tiwari ◽  
Afshin J. Ghajar
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Void Fraction ◽  
Gas Velocity ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Fraction Increase ◽  
Superficial Gas Velocity ◽  
Two Parameters

Experimental data for the void fraction and two-phase frictional pressure drop from various sources has been compiled and analyzed. The experimental data revealed that at the lower range of superficial gas velocity and void fraction, the variations of the two-phase frictional pressure drop with superficial gas velocity and void fraction are relatively flat. However, as the superficial gas velocity and void fraction increase to higher values, the frictional pressure drop became significantly sensitive to the two parameters. In a situation when the two-phase pressure drop is sensitive to the variation of the void fraction, it is then that the proper and accurate characterization of the void fraction becomes significant. From the experimental data, regions where the pressure drop is sensitive to the variation of the void fraction are identified and evaluated.

Study of Friction Factor and Equivalent Diameter Correlations for Annular Flow of Non-Newtonian Drilling Fluids

1987 ◽  
Vol 109 (4) ◽  
pp. 200-205 ◽  
Author(s):  
T. B. Jensen ◽  
M. P. Sharma
Keyword(s):  
Pressure Drop ◽  
Friction Factor ◽  
Field Data ◽  
Equivalent Diameter ◽  
Drilling Fluids ◽  
Pressure Gradients ◽  
Bingham Plastic ◽  
Frictional Pressure Drop ◽  
Friction Factors ◽  
Friction Factor Correlation

Published annular pressure drop field data have been compared with values predicted by the Bingham plastic and power law models. Several different equivalent diameter equations and friction factor correlations were utilized to estimate the frictional pressure gradients. The estimated frictional pressure drop gradients were then compared with the experimental gradients statistically to determine which combination of friction factor correlation and equivalent diameter equation predicted the experimental data best. Finally, new correlations for friction factors were developed. These new correlations predict the field data better than previously published correlations.

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