Home / Journals / FHMT / Vol.1, No.2, 2010
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  • Open AccessOpen Access

    ARTICLE

    ENERGY EFFECTIVENESS OF SIMULTANEOUS HEAT AND MASS EXCHANGE DEVICES

    G. Prakash Narayana, Karan H. Mistrya, Mostafa H. Sharqawya, Syed M. Zubairb, John H. Lienhard Va,†
    Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-13, 2010, DOI:10.5098/hmt.v1.2.3001
    Abstract Simultaneous heat and mass exchange devices such as cooling towers, humidifiers and dehumidifiers are widely used in the power generation, desalination, air conditioning, and refrigeration industries. For design and rating of these components it is useful to define their performance by an effectiveness. In this paper, several different effectiveness definitions that have been used in literature are critically reviewed and an energy based effectiveness which can be applied to all types of heat and mass exchangers is defined. The validity and the limitations of the various effectiveness definitions are demonstrated by way of several examples More >

  • Open AccessOpen Access

    ARTICLE

    LIQUID WATER DYNAMIC BEHAVIORS IN THE GDL AND GC OF PEMFCS USING LATTICE BOLTZMANN METHOD

    Li Chen, Hui-Bao Luan, Wen-Quan Tao*
    Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-11, 2010, DOI:10.5098/hmt.v1.2.3002
    Abstract Multi-phase lattice Boltzmann method is applied to investigate liquid water transport in th GDL and GC. The liquid water transport processes in the GDL, near the GDL-GC interfaces and in the GC are discussed. The effects of channel land on liquid water dynamic behaviors and distribution in the GDL and GC are investigated. It is found that channel land covers the GDL-GC interface where liquid water reaches changes the water distribution near the GDL-GC interface and in the GC. While channel land is apart from the GDL-GC interface where liquid water reaches changes the effects More >

  • Open AccessOpen Access

    ARTICLE

    PREDICTION OF BINARY MIXTURE BOILING HEAT TRANSFER IN SYSTEMS WITH STRONG MARANGONI EFFECTS

    Kenneth M. Armijo, Van P. Carey*
    Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-6, 2010, DOI:10.5098/hmt.v1.2.3003
    Abstract This paper investigates the impact of Marangoni phenomena for low concentrations of 2-propanol/water and methanol/water mixtures. In real systems the addition of small levels of surface-active contaminants can affect the surface tension of the liquid-vapor interface and thermodynamic conditions in this region. Analysis was performed for three widely accepted binary mixture correlations to predict heat flux and superheat values for subatmospheric experimental data using bulk fluid and film thermodynamic properties. Due to the non-ideal nature of these alcohol/water mixtures, this study also employs an average pseudo single-component (PSC) coefficient in place of an ideal heat… More >

  • Open AccessOpen Access

    ARTICLE

    MICROCANTILEVERS IN BIOMEDICAL AND THERMO/FLUID APPLICATIONS

    Khalil Khanafera, Kambiz Vafaib,*
    Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-9, 2010, DOI:10.5098/hmt.v1.2.3004
    Abstract A study was conducted to demonstrate the applications of microcantilevers in biomedical and thermo/fluid fields. The deflection of the microcantilevers due to biomaterial and turbulence effects was highlighted in this work. The novel patented microcantilever assemblies that were presented in this study can increase the signal and decrease the unfavorable deflection due to flow disturbances. This work paves the road for researchers in the area microcantilever based biosensors to design efficient microsensor systems that exhibit minimal errors in the measurements. Fluid-structure interaction was also utilized to investigate some aspects of the fluid flow and heat More >

  • Open AccessOpen Access

    ARTICLE

    HEAT FLOW IN THIN FILMS VIA SURFACE PHONON-POLARITONS

    Dye-Zone A. Chen, Gang Chen*
    Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-6, 2010, DOI:10.5098/hmt.v1.2.3005
    Abstract We present a calculation of the thermally generated electromagnetic flux propagating along the in-plane direction of a polar, thin film. The approach is based on fluctuational electrodynamics and the fluctuation-dissipation theorem. We find that for silicon carbide films between 5 nm and 100 nm thick, the thinner films transport more in-plane flux due to the long propagation length of the anti-symmetric surface phonon-polariton mode. Comparison of results obtained from the fluctuation-dissipation approach and the kinetic theory approach shows favorable agreement. More >

  • Open AccessOpen Access

    ARTICLE

    HOT WATER COOLED HEAT SINKS FOR EFFICIENT DATA CENTER COOLING: TOWARDS ELECTRONIC COOLING WITH HIGH EXERGETIC UTILITY

    Peter Kastena, Severin Zimmermanna, Manish K. Tiwaria, Bruno Michelb, Dimos Poulikakosa,*
    Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-10, 2010, DOI:10.5098/hmt.v1.2.3006
    Abstract Electronic data center cooling using hot water is proposed for high system exergetic utility. The proof-of-principle is provided by numerically modeling a manifold micro-channel heat sink for cooling microprocessors of a data center. An easily achievable 0.5l/min per chip water flow, with 60°C inlet water temperature, is found sufficient to address the typical data center thermal loads. A maximum temperature difference of ~8°C was found between the solid and liquid, confirming small exergetic destruction due to heat transport across a temperature differential. The high water outlet temperature from the heat sink opens the possibility of More >

  • Open AccessOpen Access

    ARTICLE

    EXPERIMENTAL STUDY OF ENHANCED NUCLEATE BOILING HEAT TRANSFER ON UNIFORM AND MODULATED POROUS STRUCTURES

    Calvin Hong Lia, G. P. Petersonb,*
    Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-10, 2010, DOI:10.5098/hmt.v1.2.3007
    Abstract An experimental investigation of the Critical Heat Flux (CHF) and heat transfer coefficient (HTC) of two-phase heat transfer of de-Ionized (DI) water, pool boiling was conducted using several kinds of sintered copper microparticle porous uniform and modulated structures. The modulated porous structure reached a heat flux of 450 W/cm2 and a heat transfer coefficient of 230,000 W/m2K. The thick and thin uniform porous structures achieved CHFs of 290 W/cm2 and 227 W/cm2 , respectively, and heat transfer coefficients of 118,000 W/m2K and 104,000 W/m2K. The mechanisms for the dramatically improved CHFs and HTCs were identified with assistance of More >

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