Entropy analysis of buoyancy driven gas–liquid two-phase flow: Analytical and experimental approaches

Hanafizadeh, Pedram; Eshraghi, Javad; Amini, Ali

doi:10.1016/j.euromechflu.2016.06.006

Cited by 5 publications

(5 citation statements)

References 21 publications

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“…The experimental data obtained for vertical slug and churn flows are listed in Table 1 in which the gas mass fraction x has a relationship with RGL as (23) in which the superficial velocity of liquid was measured directly. The actual density of two-phase flow was determined from Equation (17) and the homogenous density ρ H was computed by the Equations (2) and (24).…”

Section: Resultsmentioning

confidence: 99%

“…The thermodynamic entropy for two-phase flow was derived by Wallis [28] in the particular case of a homogeneous two-phase flow and was considered to be valid for separated two-phase flow. Similar approach was adopted by Hanafizadeh et al [24]. For steady equilibrium gas-liquid two-phase flow in pipes, the total entropy generation rate is defined as the followings [28]  …”

Section: Entropy Generation For Two-phase Flowmentioning

confidence: 99%

“…The thermodynamic entropy for two-phase flow was derived by Wallis [ 28 ] in the particular case of a homogeneous two-phase flow and was considered to be valid for separated two-phase flow. Similar approach was adopted by Hanafizadeh et al [ 24 ]. For steady equilibrium gas–liquid two-phase flow in pipes, the total entropy generation rate is defined as the followings [ 28 ]

where A is the cross-sectional area of pipe,

is the total entropy generation rate per unit length caused by irreversible processes and heat transfer in two-phase flow, s G is the specific entropy of gas, s L is the specific entropy of liquid, v m is the mean velocity of two-phase flow, x is gas mass fraction or vapor quality, z is the location coordinate along pipe, ρ H is the homogenous density of two-phase flow, and the product

is the mass flow rate of two-phase mixture.…”

Section: Entropy Generationmentioning

confidence: 99%

“…For nanofluid and ferrofluid flows, the entropy generations were studied with two-phase methods [ 19 , 20 , 21 , 22 ]. Based on separated two-phase flow model, several approaches were proposed for estimating the entropy generations in adiabatic two-phase flows [ 23 , 24 ]. In some cases, entropy can be used to predict two-phase flow parameters.…”

Section: Introductionmentioning

confidence: 99%

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Entropy Generation for Negative Frictional Pressure Drop in Vertical Slug and Churn Flows

Liu

Huang

2021

Entropy

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It is widely accepted that the frictional pressure drop is impossible to be negative for pipe flow. However, the negative frictional pressure drops were observed for some cases of two-phase slug and churn flows in pipes, challenging the general sense of thermodynamic irreversibility. In order to solve this puzzling problem, theoretical investigations were performed for the entropy generation in slug and churn flows. It is found that the frictional pressure drop along with a buoyancy-like term contributes to the entropy generation due to mechanical energy loss for steady, incompressible slug and churn flows in vertical and inclined pipes. Experiments were conducted in a vertical pipe with diameter as 0.04 m for slug and churn flows. Most of the experimental data obtained for frictional pressure drop are negative at high gas–liquid ratios from 100 to 10,000. Entropy generation rates were calculated from experimental data. The results show that the buoyancy-like term is positive and responsible for a major part of entropy generation rate while the frictional pressure drop is responsible for a little part of entropy generation rate, because of which the overall entropy generation due to mechanical energy loss is still positive even if the frictional pressure drop is negative in vertical slug and churn flows. It is clear that the negative frictional pressure drops observed in slug and churn flows are not against the thermodynamics irreversibility.

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Section: Resultsmentioning

confidence: 99%

Section: Entropy Generation For Two-phase Flowmentioning

confidence: 99%

“…The thermodynamic entropy for two-phase flow was derived by Wallis [ 28 ] in the particular case of a homogeneous two-phase flow and was considered to be valid for separated two-phase flow. Similar approach was adopted by Hanafizadeh et al [ 24 ]. For steady equilibrium gas–liquid two-phase flow in pipes, the total entropy generation rate is defined as the followings [ 28 ]

where A is the cross-sectional area of pipe,

is the mass flow rate of two-phase mixture.…”

Section: Entropy Generationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Entropy Generation for Negative Frictional Pressure Drop in Vertical Slug and Churn Flows

Liu

Huang

2021

Entropy

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“…Furthermore, the method used also provides the interrelation between the total length of pipeline when crushing is economical and the different particle size distributions [11]. Different researches on twophase flow rotordynamic multiphase pump are conducted during the recent years [12][13][14][15]. In [12], different pumped two-phase flow cooling technologies for electronic components were presented.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of a Centrifugal Pump Hydraulic Performance in Hydraulic Transmission of Solids

Barmaki

Ehghaghi

2019

Mechanics and Mechanical Engineering

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In petroleum and mine industries, the centrifugal pumps were used for transferring solid particles with water. This method is preferable to other methods because of its user friendly and economic issues. In this article by selecting a proper pump and designing test circuit, we conducted hydraulic tests for water and water mixture with solid particles. For this purpose, an experimental set-up of centrifugal pump with only water and water with solid particles was developed. Then by analyzing the test results and efficiency equation, optimal coefficients of head loss is provided to improve the pump efficiency during hydraulic transmission of solids. The experimental results of power consumption, head, and pressure difference measurements in solid–liquid systems are presented. The experimental set-up results are compared with simulation and numerical one, which show a good agreement with them. It reveals that by adding the solid particles and increasing the fluid density up to 15%, the consumed power increases by about 20%, which result in dropping the efficiency of hydraulic system up to 6%. Finally, the optimal components for developed cycle presented for evaluation the various configuration and hydraulic analysis of pure flow and flow with solid particles in various applications to enhance the most achievable efficiency.

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Development of the entropy generation investigation for slug flow in a large diameter pipe

Mohammadi

Jahangiri

Emamzadeh

et al. 2023

International Communications in Heat and Mass Transfer

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Entropy analysis of buoyancy driven gas–liquid two-phase flow: Analytical and experimental approaches

Cited by 5 publications

References 21 publications

Entropy Generation for Negative Frictional Pressure Drop in Vertical Slug and Churn Flows

Entropy Generation for Negative Frictional Pressure Drop in Vertical Slug and Churn Flows

Experimental Investigation of a Centrifugal Pump Hydraulic Performance in Hydraulic Transmission of Solids

Development of the entropy generation investigation for slug flow in a large diameter pipe

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