A Review of Prediction Methods for Two-Phase Pressure Loss in Mini/Micro-Channels

2016 ◽  
Vol 24 (01) ◽  
pp. 1630002 ◽  
Author(s):  
Jung Hoon Yun ◽  
Ji Hwan Jeong

Previous methods and correlations for predicting two-phase frictional pressure loss in mini/micro-channels are reviewed and compared. The empirical correlations are classified into four groups of modeling approaches: Homogeneous equilibrium models (HEMs), separated flow models (SFMs), direct empirical correlations, and flow pattern specific correlations. In order to examine the characteristics of the predictive methods for two-phase pressure loss in mini-channels and to assess the accuracy of the previous models and correlations, extensive experimental data and correlations that are available in the open literature are collected. The 1175 and 1304 experimental data for the two-phase pressure drop for condensing and boiling flows, respectively, are gathered from 15 papers and reports. The results present that the size of the channel significantly influences the pressure drop. The comparison demonstrates that Cicchitti et al.’s two-phase viscosity model is recommended for predicting two-phase pressure loss when the HEM is used. In general, the SFM with the two-phase multipliers of Muller–Steinhagen and Heck and Kim and Mudawar outperforms others for channel diameters of less than 3[Formula: see text]mm.

Author(s):  
Ting Xiong ◽  
Bo Wen ◽  
Yuanfeng Zan ◽  
Xiao Yan

In order to obtain the hydraulic resistance characteristics of steam generator (SG) tube support plates (TSP), experimental as well as CFD studies have been carried out on both the single-phase and two-phase hydraulic resistances of various trefoil or quatrefoil orifice plates. Results show that with the increase of the Renylod number, the single-phase pressure drop coefficient decreases firstly and remains almost constant later. The single-phase pressure drop coefficient decreases with the increase of the chamfer radius of orifice or flow area. The two-phase pressure drops predicted by the empirical correlations are generally larger than the experimental results, while the pressure drops predicted by CFD software agree with the experimental data.


Author(s):  
Hao Peng ◽  
Xiang Ling

Rigorous two-phase flow modeling is one of the great challenges in the thermal sciences. A two-dimensional computational fluid dynamics (CFD) simulation of air-water two-phase pressure drop characteristics in micro-channels by using volume of fluid (VOF) method was carried out in this paper. The simulations were performed in a horizontal micro-channel with a diameter of 1.1 mm and a length of 200 mm. Firstly, a variety of air-water two-phase flow patterns (including bubbly, slug, slug-annular and annular flow) were simulated in order to validate the feasibility and reliability of the VOF method. Next to that, the two-phase pressure drops in micro-channel were analyzed numerically by using the same CFD method. Also the comparison of pressure drop among the numerical simulations, experimental data and the results calculated by homogeneous equilibrium model was presented. The agreement between numerical results and the existing experimental data was found to be satisfactory. Based on this good agreement, it is finally found that the numerical analysis procedure proposed in this paper can be used to achieve a better prediction for micro-channel air-water flow characteristics.


Author(s):  
Wei Li ◽  
Kunrong Shen ◽  
Boren Zheng ◽  
Xiang Ma ◽  
S. A. Sherif ◽  
...  

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.


Author(s):  
H. L. Mo ◽  
R. Prattipati ◽  
C. X. Lin

Pressure drop characteristics of R134a in annular helicoidal pipe was investigated experimentally with R134a flowing in the annular section. The experimental results revealed that when more R134a vapor was condensed, the liquid phase pressure drop increased largely while the vapor phase pressure drop decreased slightly. By comparing with the experimental data obtained from the same test section with R134a flowing in the inner circular tube of the helicoidal pipe, it was observed that the pressure drop for refrigerant in the annular section was always larger. It was also observed that the helicoidal pipe orientation showed little effect on the pressure drop variations. A pressure drop correlation was developed from the experimental data in terms of pressure drop multiplier with respect to Lockhart-Martinelli parameter.


1983 ◽  
Vol 48 (12) ◽  
pp. 3356-3369 ◽  
Author(s):  
Vladimír Jiřičný ◽  
Vladimír Staněk

The paper gives a review of present approaches to the problem of a single- and two-phase flow in a packed bed. A new definititon has been given of the flooding point, which, as far as the theory is concerned, rigorously defines critical values of the quantities in the flooding point. At the same time, the definition enables a unambiguous experimental determination of the flooding point from experimental dependence sof the hold-up or pressure drop on the flow rate of phases. Based on extensive experimental data three alternative forms have been proposed of the versatile correlation of liquid hold-up on the velocity of liquid at the zero velocity of gas. The correlations have been formulated on the principle of automodel properties and define the appropriate relationships in terms of normalized variables related to the newly defined flooding point. The dependences on the geometry parameters of the packing and physical properties of liquid appear in the versatile correlations only implicitly. A new possibility has been shown of inverse utilization of the versatile correlations for the determination of the critical values (the flooding point) from two independent measurements of liquid hold-up in a real apparatus.


2012 ◽  
Vol 1 (3) ◽  
pp. 168 ◽  
Author(s):  
Arun Autee ◽  
S.Srinivasa Rao ◽  
Ravikumar Puli ◽  
Ramakant Shrivastava

Effect of inclination on two-phase frictional pressure drop was investigated in small diameter circular tubes with inner diameters of 4.0, 6.0, 8.0 and 10.0 mm using air and water. Pressure drop was measured and compared with various existing models commonly used for macro and micro channels such as homogeneous, Lockhart-Martinelli, Chisholm, Friedel, Mishma Hibiki, and Zang Mishma. It was found that existing correlations are inadequate in predicting pressure drop for small diameter inclined tubes. The void fraction is calculated using a general void fraction correlation in two-phase flow for various pipe orientations. Based on analysis of present experimental frictional pressure drop data, a correlation is proposed for predicting Chisholm parameter C in small diameter inclined tubes. There was a significant ordering of pressure drop data with respect to Reynolds number, Webber number and Bond number for each diameter.


2014 ◽  
Vol 18 (2) ◽  
pp. 521-532 ◽  
Author(s):  
Arun Autee ◽  
Srinivasa Rao ◽  
Ravikumar Puli ◽  
Ramakant Shrivastava

Experimental results of adiabatic two-phase pressure drop in small diameter tubes are presented in this work. Air-water mixture is used as the working substance. Four test sections made of transparent acrylic tubes of different internal diameters ranging from 3.0 mm to 8.0 mm are used with different test section lengths from 150 mm to 400 mm. The investigation is carried out within the range of mass flux of water 16.58 -3050 kg/m2s, mass flux of air 8.25-204.10 kg/m2s and total mass flux 99.93-3184.69 kg/m2s. Some of the existing correlations for macro and mini-channels are compared with the experimental data. Based on the experimental data; a new correlation has been developed to predict two-phase pressure drop in horizontal channels.


2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Mehmet Sorgun ◽  
Erman Ulker

Determining pressure loss for cuttings-liquid system is very complicated task since drillstring is usually rotating during drilling operations and cuttings are present inside wells. While pipe rotation is increasing the pressure loss of Newtonian fluids without cuttings in an eccentric annulus, a reduction in the pressure loss for cuttings-liquid system is observed due to the bed erosion. In this study, cuttings transport experiments for different flow rates, pipe rotation speeds, and rate of penetrations (ROPs) are conducted. Pressure loss within the test section and stationary and/or moving bed thickness are recorded. This study aims to predict frictional pressure loss for solid (cuttings)–liquid flow inside horizontal wells using computational fluid dynamics (CFD) and artificial neural networks (ANNs). For this purpose, numerous ANN structures and CFD models are developed and tested using experimental data. Among the ANN structures, TrainGdx–Tansig structure gave more accurate results. The results show that the ANN showed better performance than the CFD. However, both could be used to estimate solid–liquid two-phase pressure drop in horizontal wellbores with pipe rotation.


2015 ◽  
Vol 19 (5) ◽  
pp. 1791-1804 ◽  
Author(s):  
Arun Autee ◽  
Srinivasa Rao ◽  
Ravikumar Puli ◽  
Ramakant Shrivastava

An experimental study of two-phase pressure drop in small diameter tubes orientated horizontally, vertically and at two other downward inclinations of ?= 300 and ? = 600 is described in this paper. Acrylic transparent tubes of internal diameters 4.0, 6.0, and 8.0 mm with lengths of 400 mm were used as the test section. Air-water mixture was used as the working fluid. Two-phase pressure drop was measured and compared with the existing correlations. These correlations are commonly used for calculation of pressure drop in macro and mini-microchannels. It is observed that the existing correlations are inadequate in predicting the two-phase pressure drop in small diameter tubes. Based on the experimental data, a new correlation has been proposed for predicting the two-phase pressure drop. This correlation is developed by modification of Chisholm parameter C by incorporating different parameters. It was found that the proposed correlation predicted two-phase pressure drop at satisfactory level.


Sign in / Sign up

Export Citation Format

Share Document