Analysis of flow pattern and heat transfer in direct contact condensation

Gulawani, Sagar S.; Dahikar, Sachin K.; Mathpati, Channamallikarjun S.; Joshi, Jyeshtharaj B.; Shah, Manish S.; RamaPrasad, Chaganti S.; Shukla, Daya S.

doi:10.1016/j.ces.2008.12.020

Cited by 69 publications

(17 citation statements)

References 46 publications

(80 reference statements)

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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%

“…Compared to the full Eulerian model in [6][7][8], the model solves smaller number of variables; and therefore, it is assumed to be a good substitute for Eulerian model in several cases, including the simulation in the present work.…”

Section: Mixture Modelmentioning

confidence: 99%

“…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%

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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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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: Mixture Modelmentioning

confidence: 99%

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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“…Contributions were found for cross-flow arrangements [14], flow patterns due to jet interaction with liquid baths [15,16], or stirred vessels flows [17,18], though with no resort to evolving species transport.…”

Section: Introductionmentioning

confidence: 96%

Heat and mass transfer modeling during continuous flow processing of fluid food by direct steam injection

Bonis

Ruocco

2010

International Communications in Heat and Mass Transfer

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Experimental study of direct contact steam condensation in structured packing

Liu

Cui

et al. 2013

Asia-Pacific J Chem Eng

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An experimental study of direct contact steam condensation has been conducted at both atmospheric and vacuum pressure, in a pilot scale column filled with Tupac 125Y structured packing. The local volumetric heat transfer coefficient of condensation determined by thermal balance has been given. The influences of the vapor and liquid flow rate, liquid temperature and operation pressure have been investigated. An empirical correlation based on dimensionless numbers has been put forward and verified by various experimental measurements, and the dimensionless numbers were calculated from the Delft hydrodynamic model of structured packing. The results will give some helpful guidance in the design and operation of direct contact condensers with structured packings. Specific surface area, a p (m 2 m À3 ) 126.55 Corrugation base length, b (m) 0.042 Corrugation height, h (m) 0.024 Corrugation side length, s (m) 0.0319 Corrugation inclination angle, a ( ) 4 5 Void fraction, e 0.99 Opening ratio, Ω 0.08 X. LI ET AL. Asia-Pacific Journal of Chemical Engineering 658

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Analysis of flow pattern and heat transfer in direct contact condensation

Cited by 69 publications

References 46 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

Heat and mass transfer modeling during continuous flow processing of fluid food by direct steam injection

Experimental study of direct contact steam condensation in structured packing

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