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E. Lepinasse - One of the best experts on this subject based on the ideXlab platform.

  • Numerical study of nanofluids Condensation Heat Transfer in a square microchannel
    Numerical Heat Transfer Part A Applications, 2016
    Co-Authors: H. El Mghari, H. Louahlia-gualous, E. Lepinasse
    Abstract:

    This paper presents a numerical study of nanofluids Condensation Heat Transfer inside a single horizontal smooth square tube. The numerical results are compared with the previous experimental predictions. The numerical results show that the Heat Transfer coefficient could be improved within 20% by increasing the volume fraction of Cu nanoparticle by 5% or by increasing the mass flux from 80 to 110 kg/m2 s. Reducing the hydraulic diameter of the microchannel from 200 to 160 µm leads to an increase in the Condensation average Heat Transfer coefficient by 10%. A new correlation estimating the Nusselt number for the Condensation of nanofluids or pure vapor is proposed. It predicts average Condensation Heat Transfer with a good agreement with those computed.

  • Numerical study of nanofluids Condensation Heat Transfer in a square microchannel
    Numerical Heat Transfer Part A: Applications, 2016
    Co-Authors: H. El Mghari, H. Louahlia-gualous, E. Lepinasse
    Abstract:

    This study presents a numerical study of nanofluid Condensation Heat Transfer inside a single horizontal smooth square tube. The numerical results are compared to previous experimental predictions, and show that the Heat Transfer coefficient can be improved 20% by increasing the volume fraction of Cu nanoparticles by 5% or increasing the mass flux from 80 to 110 kg/m2 s. Reducing the hydraulic diameter of the microchannel from 200 to 160 µm led to an increase in average Condensation Heat Transfer coefficient of 10%. A new correlation estimating Nusselt number for Condensation of nanofluids or pure vapor is proposed. It predicts average Condensation Heat Transfer, with good agreement with the computed values.

H. El Mghari - One of the best experts on this subject based on the ideXlab platform.

  • Numerical study of nanofluids Condensation Heat Transfer in a square microchannel
    Numerical Heat Transfer Part A Applications, 2016
    Co-Authors: H. El Mghari, H. Louahlia-gualous, E. Lepinasse
    Abstract:

    This paper presents a numerical study of nanofluids Condensation Heat Transfer inside a single horizontal smooth square tube. The numerical results are compared with the previous experimental predictions. The numerical results show that the Heat Transfer coefficient could be improved within 20% by increasing the volume fraction of Cu nanoparticle by 5% or by increasing the mass flux from 80 to 110 kg/m2 s. Reducing the hydraulic diameter of the microchannel from 200 to 160 µm leads to an increase in the Condensation average Heat Transfer coefficient by 10%. A new correlation estimating the Nusselt number for the Condensation of nanofluids or pure vapor is proposed. It predicts average Condensation Heat Transfer with a good agreement with those computed.

  • Numerical study of nanofluids Condensation Heat Transfer in a square microchannel
    Numerical Heat Transfer Part A: Applications, 2016
    Co-Authors: H. El Mghari, H. Louahlia-gualous, E. Lepinasse
    Abstract:

    This study presents a numerical study of nanofluid Condensation Heat Transfer inside a single horizontal smooth square tube. The numerical results are compared to previous experimental predictions, and show that the Heat Transfer coefficient can be improved 20% by increasing the volume fraction of Cu nanoparticles by 5% or increasing the mass flux from 80 to 110 kg/m2 s. Reducing the hydraulic diameter of the microchannel from 200 to 160 µm led to an increase in average Condensation Heat Transfer coefficient of 10%. A new correlation estimating Nusselt number for Condensation of nanofluids or pure vapor is proposed. It predicts average Condensation Heat Transfer, with good agreement with the computed values.

Jiping Liu - One of the best experts on this subject based on the ideXlab platform.

  • Condensation Heat Transfer of steam on vertical micro-tubes
    Applied Thermal Engineering, 2015
    Co-Authors: Jinshi Wang, Junjie Yan, Ronghai Huang, Xiping Chen, Jiping Liu
    Abstract:

    Abstract In this paper the Condensation Heat Transfer of steam on vertical micro-tubes was investigated. Experiments were carried out under various vapour pressures and vapour velocities. Four tubes with different diameters, 0.608 mm, 0.793 mm, 1.032 mm and 1.221 mm, were included. The results showed that, with the increase in vapour-to-surface temperature difference, Condensation Heat Transfer coefficient decreased monotonously, as well as that by Nusselt's Equation on vertical surface. With the decrease in tube diameter, the Condensation Heat Transfer coefficient decreased monotonously. As the curvature effect on Heat Transfer, the experimental values of Condensation Heat Transfer coefficients were higher than the predicted values by Nusselt's Equation. The difference of Condensation Heat Transfer coefficients between different tubes was obvious. It indicated that the effect of tube diameters on Condensation Heat Transfer for micro-tubes was significant, and should be attached great importance. With the increase in vapour pressure and vapour velocity, the Condensation Heat Transfer coefficient increased. A new correlation for Condensation Heat Transfer of steam was proposed considering the effect of tube diameter and vapour velocity. For 95% of the data, the deviation between the predicted values and the experimental data is in the range of ±20%.

Jinshi Wang - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Study on Condensation Heat Transfer of Ethanol–Water Vapor Mixtures on Vertical Micro-tubes
    International Journal of Thermophysics, 2015
    Co-Authors: Xiping Chen, Jinshi Wang, Ronghai Huang, Junchao Qin, Daotong Chong, Junjie Yan
    Abstract:

    The paper presents an experimental investigation of Marangoni Condensation Heat Transfer of ethanol–water vapor mixtures on vertical micro-tubes with an outer diameter of 0.793 mm, 1.032 mm, and 1.221 mm. Experiments were performed over a wide range of ethanol mass fractions in vapor mixtures for different vapor velocities and pressures. Condensation Heat Transfer coefficients behaved nonlinear characteristics, increased, and then decreased with increasing vapor-to-surface temperature difference. Under the same experimental conditions, the Condensation Heat Transfer coefficient at a 2 % ethanol mass fraction in vapor was the highest. At low ethanol mass fractions, the Condensation Heat Transfer coefficient of the ethanol–water vapor mixture was 2 to 3 times greater than that for pure steam. The effect of vapor pressure and velocity on Condensation Heat Transfer suggested a positive tendency on each micro-tube for all vapor mixtures with different ethanol mass fraction. Results showed that Condensation Heat Transfer coefficients on micro-tubes with a diameter of 1.032 mm were higher than those on the other two micro-tubes, suggesting that there existed a critical diameter which gave the largest Condensation Heat Transfer coefficient.

  • Condensation Heat Transfer of steam on vertical micro-tubes
    Applied Thermal Engineering, 2015
    Co-Authors: Jinshi Wang, Junjie Yan, Ronghai Huang, Xiping Chen, Jiping Liu
    Abstract:

    Abstract In this paper the Condensation Heat Transfer of steam on vertical micro-tubes was investigated. Experiments were carried out under various vapour pressures and vapour velocities. Four tubes with different diameters, 0.608 mm, 0.793 mm, 1.032 mm and 1.221 mm, were included. The results showed that, with the increase in vapour-to-surface temperature difference, Condensation Heat Transfer coefficient decreased monotonously, as well as that by Nusselt's Equation on vertical surface. With the decrease in tube diameter, the Condensation Heat Transfer coefficient decreased monotonously. As the curvature effect on Heat Transfer, the experimental values of Condensation Heat Transfer coefficients were higher than the predicted values by Nusselt's Equation. The difference of Condensation Heat Transfer coefficients between different tubes was obvious. It indicated that the effect of tube diameters on Condensation Heat Transfer for micro-tubes was significant, and should be attached great importance. With the increase in vapour pressure and vapour velocity, the Condensation Heat Transfer coefficient increased. A new correlation for Condensation Heat Transfer of steam was proposed considering the effect of tube diameter and vapour velocity. For 95% of the data, the deviation between the predicted values and the experimental data is in the range of ±20%.

Maocheng Tian - One of the best experts on this subject based on the ideXlab platform.

  • Diverging/converging small channel for Condensation Heat Transfer enhancement under different gravity conditions
    International Communications in Heat and Mass Transfer, 2020
    Co-Authors: Chao Bai, Yan Qiu, Xue-li Leng, Guanmin Zhang, Maocheng Tian
    Abstract:

    Abstract Diverging-shaped small channel is considered analytically aiming to further enhance Condensation Heat Transfer inside channels. To fulfill Heat dissipation requirements under varying-gravity conditions, effectiveness of the diverging small channel is also verified under different gravities. The refrigerant mass flow rate, total Heat Transfer area and thermal boundary conditions are fixed to investigate effect of channel shape. Smaller channel possesses better overall Condensation performance, especially for small-gravity conditions. Diverging channel enhances local Condensation Heat Transfer even with very small diverging angles. Overall Condensation Heat Transfer becomes worse as diverging angle is relatively larger when channel size and gravity decrease. Converging-shaped small channel is therefore proposed and verified to effectively enhance the overall Condensation Heat Transfer performance.

  • Diverging small channel for Condensation Heat Transfer enhancement
    International Journal of Heat and Mass Transfer, 2019
    Co-Authors: Chao Bai, Hongzhen Cao, Zhang Guanmin, Maocheng Tian
    Abstract:

    Abstract Small channel Heat Transfer with Condensation or boiling is utilized to handle the more and more intense Heat dissipation load nowadays. To further enhance the annular Condensation Heat Transfer inside these channels, diverging-shaped small channel is considered in this work analytically. It is testified that diverging channels do improve Condensation Heat Transfer significantly compared to small channels with constant cross-sectional area. With refrigerant mass flux density increasing or channel size decreasing, diverging channels become more and more efficient in enhancing Condensation Heat Transfer.