CFD analysis of flow pattern and heat transfer in direct contact steam condensation

Gulawani, Sagar S.; Joshi, Jyeshtharaj B.; Shah, Manish S.; RamaPrasad, Chaganti S.; Shukla, Daya S.

doi:10.1016/j.ces.2006.03.032

Cited by 123 publications

(44 citation statements)

References 8 publications

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“…Moreover, a sharp decrease of temperature occurs at the vapor-liquid interface, while smooth decrease of temperature within 5 K is observed far away from pipe exit, e.g., liquid region. The results of numerical predictions show the similar profile as the work by Gulawani [5,6].…”

Section: Temperature Fieldsupporting

confidence: 77%

“…(1) A different mathematical model from the previous studies by other researchers is proved to be valid through the comparisons with the results obtained by Takase et al [35], Dahikar et al [7] and Gulawani [5,6]. (2) Three distinct stages of DCC are discriminated clearly at the present conditions, i.e., initial stage, developing stage and oscillatory stage.…”

Section: Discussionmentioning

confidence: 70%

“…In addition, the second order upwind discretization scheme is used for solving the momentum equations and energy equation, while a first order upwind discretization scheme is used for solving turbulent kinetic energy equations, turbulent dissipation rate equations and volume fraction equations. Considering the instability resulting from two phase flow and condensation, the under-relaxation factors are initially set to be 0.1 for all variables at the first 0.1 s, and they subsequently change to be default value for the remainder of simulation time, while the time step is 0.001 s based on the previous work conducted by other researchers [5][6][7]9]. All the simulations were performed on a workstation with four Intel computer cores and 8 GB RAM.…”

Section: Simulation Detailsmentioning

confidence: 99%

See 2 more Smart Citations

Entropy Assessment on Direct Contact Condensation of Subsonic Steam Jets in a Water Tank through Numerical Investigation

Zhang

Tong

et al. 2016

Entropy

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Abstract:The present article analyzes the dissipation characteristics of the direct contact condensation (DCC) phenomenon that occurs when steam is injected into a water tank at a subsonic speed using a new modeling approach for the entropy generation over the calculation domain. The developed entropy assessment model is based on the local equilibrium hypothesis of non-equilibrium thermodynamics. The fluid flow and heat transfer processes are investigated numerically. To describe the condensation and evaporation process at the vapor-liquid interface, a phase change model originated from the kinetic theory of gas is implemented with the mixture model for multiphase flow in the computational fluid dynamics (CFD) code ANSYS-FLUENT. The CFD predictions agree well with the published works, which indicates the phase change model combined with the mixture model is a promising way to simulate the DCC phenomenon. In addition, three clear stages as initial stage, developing stage and oscillatory stage are discriminated from both the thermal-hydraulic results and the entropy generation information. During different stages, different proportion of the entropy generation rate owing to heat transfer, viscous direct dissipation, turbulent dissipation and inner phase change in total entropy generation rate is estimated, which is favorable to deeper understanding the irreversibility of DCC phenomenon, designing and optimizing the equipment involved in the process.

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Section: Temperature Fieldsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 70%

Section: Simulation Detailsmentioning

confidence: 99%

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Entropy Assessment on Direct Contact Condensation of Subsonic Steam Jets in a Water Tank through Numerical Investigation

Zhang

Tong

et al. 2016

Entropy

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“…However, direct coupled analysis is very difficult and needs a lot of calculation time. The Computational Fluid Dynamics (CFD) method was used for simulating two-phase flow with condensation [1,2]. However, it is very difficult to consider phase equilibrium in CFD.…”

Section: Introductionmentioning

confidence: 99%

Ammonia concentration analysis for the steam condenser by combining two phase flow CFD simulation with condensation and process simulation

Karube¹,

Maekawa²,

et al. 2009

Computational Methods in Multiphase Flow V

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Ammonia corrosion in alumi-brass tubes in steam condensers can be a serious problem. It generally occurs in the high ammonia concentration area. In this case, it is planned to replace the alumi-brass tubes by higher grade material, such as cupronickel. Therefore, it is important to minimize the area to be replaced in order to keep the equipment cost down. It is known that the ammonia concentration is related to the degree of corrosion damage. We propose a hybrid analysis method to obtain ammonia concentration by combining two-phase flow Computational Fluid Dynamics (CFD) analysis and network analysis by a chemical engineering process simulator for the tube bundle. Ammonia concentration obtained by the simulation is therefore used to determine the area to be replaced by the higher grade material tubes.

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“…The above procedure has been used partially or fully by several investigators, for instance, for mixing [15,19,52,53,[59][60][61][62][63], axial mixing [64][65][66][67], heat and mass transfer [68][69][70][71][72][73], gas induction [74][75][76], solid suspension [75,77,78], and enzyme deactivation [79].…”

Section: Introductionmentioning

confidence: 99%

CFD Simulation of Annular Centrifugal Extractors

Vedantam

Wardle

Tamhane

et al. 2012

International Journal of Chemical Engineering

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Annular centrifugal extractors (ACE), also called annular centrifugal contactors offer several advantages over the other conventional process equipment such as low hold-up, high process throughput, low residence time, low solvent inventory and high turn down ratio. The equipment provides a very high value of mass transfer coefficient and interfacial area in the annular zone because of the high level of power consumption per unit volume and separation inside the rotor due to the high g of centrifugal field. For the development of rational and reliable design procedures, it is important to understand the flow patterns in the mixer and settler zones. Computational Fluid Dynamics (CFD) has played a major role in the constant evolution and improvements of this device. During the past thirty years, a large number of investigators have undertaken CFD simulations. All these publications have been carefully and critically analyzed and a coherent picture of the present status has been presented in this review paper. Initially, review of the single phase studies in the annular region has been presented, followed by the separator region. In continuation, the two-phase CFD simulations involving liquid-liquid and gas-liquid flow in the annular as well as separator regions have been reviewed. Suggestions have been made for the future work for bridging the existing knowledge gaps. In particular, emphasis has been given to the application of CFD simulations for the design of this equipment.

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CFD analysis of flow pattern and heat transfer in direct contact steam condensation

Cited by 123 publications

References 8 publications

Entropy Assessment on Direct Contact Condensation of Subsonic Steam Jets in a Water Tank through Numerical Investigation

Entropy Assessment on Direct Contact Condensation of Subsonic Steam Jets in a Water Tank through Numerical Investigation

Ammonia concentration analysis for the steam condenser by combining two phase flow CFD simulation with condensation and process simulation

CFD Simulation of Annular Centrifugal Extractors

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