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A. R. Balakrishnan

Bio: A. R. Balakrishnan is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Heat transfer & Boiling. The author has an hindex of 3, co-authored 3 publications receiving 15 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a model for nucleate pool boiling heat transfer of binary mixtures has been proposed based on an additive mechanism, which takes into account the microroughness of the heating surface which has been defined quantitatively.
Abstract: Nucleate boiling is characterized by the formation of vapor at preferred sites (nucleation sites) on a heating surface that is submerged in the liquid and maintained at a temperature above the saturation temperature of the liquid. In the present study, a model has been developed for pool boiling of binary mixtures based on an additive mechanism. Nucleate pool boiling of binary mixtures finds many applications in the refrigeration and air conditioning industry, the chemical process industries, such as the liquid natural gas industry, and in the reboilers of distillation columns among others. Here, a model for nucleate pool boiling heat transfer of binary mixtures has been proposed based on an additive mechanism. The contributing modes of heat transfer are (i) the heat transferred by microlayer evaporation, (ii) the heat transferred by transient conduction during the reformation of the thermal boundary layer, and (iii) the heat transferred by turbulent natural convection. The model takes into account the microroughness of the heating surface which has been defined quantitatively. The model compares satisfactorily with data obtained in the present study and in the literature. These data were obtained on a variety of heating surfaces such as a vertical platinum wire, a horizontal stainlessmore » steel tube and flat horizontal aluminium, and stainless steel surfaces (with various surface finishes) thereby demonstrating the validity of the model.« less

10 citations

Journal ArticleDOI
TL;DR: The perforated interference sleeve, as a boiling heat transfer enhancement technique, gives larger enhancement factors at saturated flow conditions compared to subcooled flow conditions as discussed by the authors, where the perforation is applied to the interference sleeve.
Abstract: The perforated interference sleeve, as a boiling heat transfer enhancement technique, gives larger enhancement factors at saturated flow conditions compared to subcooled flow conditions

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors evaluated two-phase heat exchangers for single-phase flows and showed that they can achieve state-of-the-art performance in terms of heat transfer.

205 citations

Journal ArticleDOI
TL;DR: In this article, a theoretical investigation for the steady-state counter flow wet cooling tower with modified definitions for both the number of transfer units and the tower thermal effectiveness is presented, where the tower effectiveness is defined by the tower cooling range and the approach to equilibrium.
Abstract: The paper describes a theoretical investigation for the steady-state counter flow wet cooling tower with modified definitions for both the number of transfer units and the tower thermal effectiveness. The modified number of transfer units is dependent on both air and water heat capacity. The effectiveness is defined by the tower cooling range and the approach to equilibrium. A new expression relating the tower effectiveness to the modified number of transfer units and the capacity rate ratio has been developed. The model considered the resistance to heat transfer in the water film, the nonunity of the Lewis number, and the curvature of the saturated air enthalpy curve. A procedure for implementing the model in designing or rating cooling towers has been outlined and demonstrated through illustrative examples. The model compares very satisfactorily with other methods such as Logarithmic Mean Enthalpy Difference (LMED) and conventional effectiveness-NTU. Within the ranges used, the obtained results showed that substantial errors varied from +4.289 to -2.536 percent can occur in calculating the cooled water outlet temperature, and errors from +42.847 to -16.667 percent can occur in estimating the tower thermal characteristics.

49 citations

Journal ArticleDOI
TL;DR: In this paper, a new correlation to estimate mixture heat transfer coefficients has been proposed in terms of an ideal heat transfer coefficient and a correction term for the presence of other liquids and it was found that the performance of literature correlations improved considerably.

46 citations

Journal ArticleDOI
TL;DR: In this paper, a step-by-step approach is employed for numerical modeling of counterflow heat and mass exchangers in a natural draft wet-cooling tower, followed by reduced order modelling of heat transfer in cooling tower fills by means of proper orthogonal decomposition radial basis function networks.
Abstract: Numerical modelling of natural draft wet-cooling towers is considered in this paper. Development of a complete CFD model capable of predicting cooling tower performance under various operating conditions is presented. A step-by-step approach is employed, thus one-dimensional numerical modelling of counterflow heat and mass exchangers is extensively presented first. This is followed by reduced order modelling of heat and mass transfer in cooling tower fills by means of proper orthogonal decomposition radial basis function networks. Then the approaches in modelling of droplet zones (rain and spray zones) are discussed. Finally the two and three-dimensional CFD models are discussed.

44 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of boiling saturated methanol or saturated and subcooled HFE-7100 on a heated surface covered with a layer of mesh were investigated and the whole boiling curves were constructed.

40 citations