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Janusz T. Cieśliński and Tomasz Z. Kaczmarczyk

Abstract

The paper deals with pool boiling of water-Al2O3 and water- Cu nanofluids on rough and porous coated horizontal tubes. Commercially available stainless steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate the test heater. The tube surface was roughed with emery paper 360 or polished with abrasive compound. Aluminium porous coatings of 0.15 mm thick with porosity of about 40% were produced by plasma spraying. The experiments were conducted under different absolute operating pressures, i.e., 200, 100, and 10 kPa. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. It was observed that independent of operating pressure and roughness of the stainless steel tubes addition of even small amount of nanoparticles augments heat transfer in comparison to boiling of distilled water. Contrary to rough tubes boiling heat transfer coefficient of tested nanofluids on porous coated tubes was lower compared to that for distilled water while boiling on porous coated tubes. A correlation equation for prediction of the average heat transfer coefficient during boiling of nanofluids on smooth, rough and porous coated tubes is proposed. The correlation includes all tested variables in dimensionless form and is valid for low heat flux, i.e., below 100 kW/m2.

Open access

Sebastian Rulik, Leszek Remiorz and Sławomir Dykas

of the Acoustical Society of America 84 (1988), 4, 1148-1180. Hantschk C.C.: Vortmeyer D.: Numerical simulation of self-excited thermoacoustic instabilities in a Rijke tube. Journal of Sound and Vibration 277 (1999), 3, 511-522. Zoontjens L.: Numerical Investigations of the Performance and Effectiveness of Thermoacoustic Couples. PhD thesis, The University of Adelaide, Adelaide 2008. Zink F., Vipperman J., Schaefer L.: CFD simulation of thermoacoustic cooling. International

Open access

Yun-Yu Chen

characterized by UV second harmonic generation. In: Proc. Nat. Aca. Sci. USA PNAS 106(2009), 36, 15176-15180. [7] Li H., Li R., Zhu H.L. et al.: Influence of electrostatic field from soil particle surfaces on ion adsorption-diffusion. Soil Sci. Soc. Am. J. 74(2010), 4, 1129-1138. [8] Eftekharibafrooei A., Borguet E.: Effect of electric fields on the ultrafast vibrational relaxation of water at a charged solid-liquid interface as probed by vibrational sum frequency generation. J. Phys. Chem. Lett. 2(2011), 12, 1353-1358. [9

Open access

Mohamed I. Othman and Ahmed E.E. Abouelregal

rajkowski D., C ukic R.: A coupled problem of thermoelastic vibrations of a circular plate with exact boundary conditions. Mech. Res. Commun. 26 (1999), 2, 217–224. [13] W ang X., X u X.: Thermoelastic wave induced by pulsed laser heating. Appl. Phys. A, 73 (2001), 1, 107–114. [14] M c D onald F.A.: On the precursor in laser-generated ultrasound waveforms in metals. Appl. Phys. Lett. 56 (1990), 3, 230–232. [15] A llam M.N.M., A boulregal A.E.: The thermoelastic waves induced by pulsed laser and varying heat of non-homogeneous microscale

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Manindra Mitra and Rabindra Kumar Bhattacharyya

micropolar materials with voids. J. Comput. Appl. Math. 70(1996), 1, 115-126. [6] Marin M.: A domain of influence theorem for microstretch elastic materials. Non- Linear Analysis: Real World Applications 11(2010), 5, 3446-3452. [7] Marin M., Lupu M.: On harmonic vibrations in thermoelasticity of micropolar bodies. J. Vib. Control 4(1998), 5, 507-518. [8] Marin M., Marinescu C.: Thermoelasticity of initial ly stressed bodies, asymptotic equipartition of energies. Int. J. Eng. Sci. 36(1998), 1, 73-86. [9] Kumar

Open access

Jakub Kajurek, Artur Rusowicz and Andrzej Grzebielec

ling of the thermoacoustic engine. Arch. Thermodyn. 32(2011), 3, 175-190. [12] Tijani M.E.H., Zeegers J.C.H., de Waele A.T.A.M.: Design of thermoacoustic refrigerators. Cryogenics 42(2002), 49-57. [13] Backhaus S., Swift G.: New varieties of thermoacoustioc engines. In: Proc. 9th Int. Con. on Sound and Vibration, 2002. [14] Tijani M.E.H., Zeegers J.C.H., de Waele A.T.A.M.: The optimal stack spacing for thermoacoustic refrigeration. J. Acoust. Soc. Am. 112(2002), 1, 128-133. [15] Tijani M.E.H., Zeegers J

Open access

Mohamed I.A. Othman, Ramadan S. Tantawi and Ebtesam E.M. Eraki

inserted liquid samples. J. Appl. Phys. 36(1965), 1, 3-8. [9] Kreuzer L.B.: Ultralow gas concentration infrared absorption spectroscopy. J. Appl. Phys. 42(1971), 7, 2934-2943. [10] Todorovic D.M., Nikolic P.M., Bojicic A.I.: Photoacoustic frequency transmission technique: Electronic deformation mechanism in semiconductors. J. Appl. Phys. 85(1999), 7716-7726. [11] Song Y.Q., Todorovic D.M., Cretin B.: Study on the generalized thermoelastic vibration of the optical ly excited semiconducting micro-cantilevers. Int. J. Solids