Constitutive equations for vertical upward two-phase flow in rod bundle

Hibiki, Takashi; Ozaki, Tetsuhiro; Shen, Xiuzhong; Miwa, Shuichiro; Kinoshita, Ikuo; Hazuku, Tatsuya; Rassame, Somboon

doi:10.1016/j.ijheatmasstransfer.2018.08.067

Cited by 15 publications

(4 citation statements)

References 53 publications

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“…Based on a certain hypothesis, the constitutive equation is obtained as (Hibiki et al , 2018): where σ ij is deviatoric stress tensor, ζ ij is second order unit tensor, ui uj uk are the velocity of each component, xi xj xk are the coordinate of each component in space, p is the equal pressure.…”

Section: Theory and Methodsmentioning

confidence: 99%

Effect of fish scale texture on friction performance for reciprocating pair with high velocity

Quan

Guo

Gong

et al. 2019

ILT

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Purpose This paper aims to study the frictional performance of reciprocating pair with high velocity by using hydrodynamic lubrication principle and fish scale textured piston model. Design/methodology/approach Based on the idea of function characteristic approximation and coordinate change, a mathematical representation model of imitating fish scale texture pit section is established. According to the principle of dynamic pressure lubrication of the textured fluid, a three-dimensional numerical model of flow field for fish scale texture is established without considering cavitation. Numerical analysis of the model carp scale texture unit by orthogonal experimental design and FLUENT software is carried out. Findings Effects of fish scale pit texture on friction properties for a reciprocating pair piston surface with high velocity (impact piston) are acquired. Effects of texture characterization parameters and flow rate on the surface friction performance for impact piston are found. Effects of different characteristic parameters combination of imitating fish scale texture on friction performance for impact piston surface are obtained. Originality/value The model is an effective tool to study the friction and wear of reciprocating pair with high velocity. The effects of fish scale textured piston pair supply a theory lead to design the reciprocating pair with better friction performance. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2019-0398

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Section: Theory and Methodsmentioning

confidence: 99%

Effect of fish scale texture on friction performance for reciprocating pair with high velocity

Quan

Guo

Gong

et al. 2019

ILT

View full text Add to dashboard Cite

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“…where σ, ρ f , ρ g , and g are surface tension, liquid and gas phase densities, and gravitational acceleration respectively. Hibiki et al (2018) reviewed various drift-flux correlations of the C 0 and V gj for the rod bundle flow channel. They recommended the following correlations of Ozaki et al (2013) for the two-phase flow in the rod bundle flow channel, which were developed from the upwardly-flowing boiling water data taken in a vertical 8×8 rod bundle under high temperature and pressure conditions:…”

Section: Radial Profiles Of Local Gas Velocitymentioning

confidence: 99%

“…The IAC correlation working as the important constitutive model for the two-fluid model is often used to predict the <a i > in the two-phase flow. Limited work has been conducted on developing the IAC correlation in a rod bundle flow channel (Hibiki et al, 2018). The existing IAC correlations developed for circular pipes are usually tested in the two-phase flow in the rod bundle flow channel as Hibiki et al (2006), , and Shen and Deng (2016) did.…”

Section: Area-averaged Iac and Its Comparison With Iac Correlation Prmentioning

confidence: 99%

Local measurements of upward air-water two-phase flows in a vertical 6×6 rod bundle

Shen

Miwa

Xiao

et al. 2019

Exp. Comput. Multiph. Flow

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A 3 m high vertical rod bundle flow channel consisting of 6×6 rods with the rod diameter of 10 mm and the pitch of 16.7 mm and a channel box with the cross section of 100 mm × 100 mm was used to study the local two-phase flow characteristics under influences of the 36 rods and the channel box. The air and water were selected as the two-phase working fluids in the present experiments. A double-sensor probe installed at the axial position of z/DH = 149 and six evenly-installed differential pressure (DP) gauges measured the upward-moving two-phase flow in the rod bundle flow channel under the atmospheric condition. Since the local parameters of void fraction, interfacial area concentration (IAC), bubble diameter, and gas velocity are essential to know the internal structures of the two-phase flow, their data at 16 points within an octant symmetric triangular area of the flow channel cross section were collected by the double-sensor probe under various flow conditions in the experiments. The local measurements of double-sensor probe were found to agree well with the void fractions from the DP gauges and the superficial gas velocity from a gas flowmeter. Both the measured void fractions and IACs displayed a transition from radial wall-peaking profile to radial core-peaking profile in the low superficial liquid velocity flow conditions and pure radial wall-peaking profiles in the high superficial liquid velocity flow conditions. The measured Sauter mean diameters showed their radial wall-peaking profiles with the peaking degree decreasing with the increasing superficial gas velocity in both the low and high superficial liquid velocity flow conditions. The measured gas velocities in the main flow direction showed a transition from a radial nearly-flat profile or a radial mid-peaking profile to radial core-peaking profiles in the low and high superficial liquid velocity flow conditions. The area-averaged void fractions and IACs integrated from their measured local values were respectively compared with the predictions of existing drift-flux and IAC correlations. The comparison results showed that the drift-flux correlation of Ozaki et al. (2013) and the IAC correlation of Shen and Deng (2016) give the reasonable prediction and can be recommended for the predictions of the void fraction and the IAC respectively in the bubbly flows in the rod bundle flow channel. Keywords 6×6 rod bundle flow channel gas-liquid two-phase flow void fraction interfacial area concentration double-sensor probe

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“…The successful development of the interfacial area transport equation is considered to have produced a significant improvement in the two-fluid model formulation and the prediction accuracy of system codes. The interfacial area concentration has thus been studied experimentally and theoretically over the past twenty years Lin and Hibiki, 2014;Chuang and Hibiki, 2015;Hibiki et al, 2018). At the first stage of the development of the interfacial area transport equation, the equation for the flow in conventional-size pipes was successfully developed by modeling the sink and source terms of the interfacial area concentration due to bubble coalescence and breakup (Liu and Hibiki, 2018;.…”

Section: Introductionmentioning

confidence: 99%

Measurement of local two-phase flow parameters of downward bubbly flow in mini pipes

Hazuku

Ihara

Hibiki

2019

Exp. Comput. Multiph. Flow

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In order to extend a precise database on local two-phase flow parameters in mini pipes, experiments were conducted for adiabatic gas-liquid bubbly flows flowing down in vertical mini pipes with inner diameters of 1.03, 3.00, and 5.00 mm. A stereo image-processing was applied to observe the phase distribution characteristics in pipe cross-section. The local flow parameters including profiles of void fraction, Sauter mean bubble diameter, and interfacial area concentration in pipe cross-section were obtained at three axial locations in the test pipes with various flow conditions: superficial gas velocity of 0.00508-0.0834 m/s and superficial liquid velocity of 0.208-3.00 m/s. The axial developments of the local flow parameters were discussed in detail based on the obtained data and the visual observation. It was confirmed that the core peak distributions were formed at low liquid flow rate conditions in which the buoyancy force dominated while the wall peak distributions were formed at high liquid flow rate conditions in which the body acceleration due to the frictional pressure gradient dominated. The result indicated the existence of lift force pushing the bubbles towards the pipe wall even in vertical downward flows. The database obtained through the present experiment is expected to be useful in modeling the interfacial area transport terms, the validation of the existing lift force models as well as the benchmarking of various CFD simulation codes.

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Constitutive equations for vertical upward two-phase flow in rod bundle

Cited by 15 publications

References 53 publications

Effect of fish scale texture on friction performance for reciprocating pair with high velocity

Effect of fish scale texture on friction performance for reciprocating pair with high velocity

Local measurements of upward air-water two-phase flows in a vertical 6×6 rod bundle

Measurement of local two-phase flow parameters of downward bubbly flow in mini pipes

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