SVIBOR - Papers - project code: 2-08-204

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Published papers on project 2-08-204


Quoted papers: 1
Other papers: 13
Total: 14


  1. Type of paper: Paper in proceedings

    Title: Experimental Equipment for Measuring Boiling Heat Transfer from Vibrating Surface

    Authors:
    Žitko, Vinko (55624)
    Lučin, Davor
    Afgan, Naim
    Editors
    Allmer, Hans
    Feretić, Danilo
    Jelaska, Damir
    Orgelmeister, Hans
    Pažanin, Josip
    Srb, Neven
    Proceedings title: Zbornik radova broj 4 sa 3. međunarodnog simpozija o novim tehnologijama
    Language: hrvatski
    Place: Zagreb
    Year: 1991
    Pages: from 184 to 192
    Meeting: 3. međunarodni simpozij o novim tehnologijama
    Held: from 10/15/91 to 10/17/91
    Summary: Heat transfer is present as an important factor in problems ofmany engineering areas, therefore there are justified reasons forresearching the possibility of its improvement. This paper is anintroduction to the subject belonging to one of already openedchapters in studying the possibilities of heat transferimprovement, i.e. the influence of vibrations on heat transfercoefficient at pool boiling. The paper deals with theconstruction of experimental equipment the aim of which is toimplement the research of the influence of vertical vibrations ofa horizontal heating surface on heat transfer coefficient at poolboiling. The results of the experimental series of measurementsconfirming the hypothesis of the possibility of improvement ofheat transfer coefficient by vibration of the system arepresented.
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration

  2. Type of paper: Paper in proceedings

    Title: Boiling Heat Transfer from Oscillating Surface

    Authors:
    Žitko, Vinko (55624)
    Afgan, Naim
    Editors
    Lorenzo, Enrico
    Salvisigni, Sandro
    Proceedings title: Atti del X Congresso Nazionale sulla Trasmissione del Calore
    Language: engleski
    Place: Genova, Italia
    Year: 1992
    Pages: from 321 to 330
    Meeting: X Congresso Nazionale sulla Trasmisione del Calore
    Held: from 06/25/92 to 06/27/92
    Summary: The paper describes the fundamental experimental research of the pool boiling heat transfer occurring during the vibration ofheating surface and the liquid in contact with it. Experimentsare performed on the vibrating table (Shipbuilding Institute inZagreb) with an equipment made specifically for this purpose, andwith the aim of stating the heat transfer coefficient ( ŕ ) atthe boiling point. The equipment is designed so as to withstandall the highest stresses caused by applied vibration and thermal parameters and to provide the advanced water pool boilingoccurring at atmospheric pressure. Measurements are made byvarying thermodynamic parameters such as: heat flux q = 0 - 85 * 10exp(4) W/m2 amplitude A = 0.1 - 2.0 *10exp(-3) m frequency f = 0 - 70 Hz. On account of data processing and analysis we can conclude thatthe heat transfer coefficient increases with the value of heatflux. We can also notice that with the increase of frequency andamplitude the heat transfer coefficient increases up to 25%.
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration

  3. Type of paper: Paper in proceedings

    Title: Boiling Heat Transfer of Ethyl Alcohol from Vibrating Surface

    Authors:
    Žitko, Vinko (55624)
    Editors
    Faggiani, Sergio
    Del Tin, Giovanni
    Lorenzini, Enrico
    Oliveri, Elio
    Pisoni, Claudio
    Salvigni, Sandro
    Vigni, Piero
    Proceedings title: Atti del XI Congresso Nazionale sulla Trasmissione del Calore
    Language: engleski
    Place: Milano, Italia
    Year: 1993
    Pages: from a10 to a16
    Meeting: XI Congresso Nazionale sulla Trasmissione del Calore
    Held: from 06/24/93 to 06/26/93
    Summary: The paper describes the fundamental experimental research of the pool boiling heat transfer occurring during the vibration of heating surface and the liquid in contact with it. The advanced ethyl-alcohol pool boiling occurring at atmospheric pressure is performed with an equipment made specifically for this purpose. For the applied heat flux and vibration parameters the functional relations and the coefficient of heat transfer from the heating plane to ethyl-alcohol are given. Analysing the results, the improvement of the heat transfer coefficient in relation to nonvibrating state can be noticed. This improvement is a bit smaller in relation to the same treatment applied to water as a treated medium, which are the results presented on the X-th National Heat Transfer Conference (25 - 27 June 1992, Genoa, Italy).
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration

  4. Type of paper: Paper in proceedings

    Title: Boiling Heat Transfer in the Ethyl Alcohol and Water from the Oscillating Surface

    Authors:
    Žitko, Vinko (55624)
    Afgan, Naim
    Editors
    Carvalho, Maria
    Bar-Cohen, A.
    Rotzel, W.
    Butterword, D.
    Proceedings title: The Proceedings of 1993 ICHMT Internat. Symp. on New Develop. in Heat Exchangers
    Language: engleski
    Place: Lisabon, Portugal
    Year: 1993
    Pages: from 223 to 228
    Meeting: 1993 ICHMT International Symposium on New Developments in Heat Exchangers
    Held: from 09/06/93 to 09/10/93
    Summary: Paper describes experimental research of pool boiling heattransfer from the oscillating heating surface. Specially designedapparatus for pool boiling heat transfer measurements fromoscillating heating surface was described with special referenceto oscillating control and heat transfer parameters measurements.In the frequency range 0-70 Hz the boiling heat transfercoefficient was determined for the heat flux range q < 50 W/cm2.Special emphases is given to the effect of the oscillatingamplitude within the range A = 0,5 - 2 mm. Obtained experimentaldata for water and ethyl alcohol boiling have been correlated tothe reference state of nonvibrating heating surface. It was shownthat within the range if experimental parameters that boilingheat transfer coefficient is function oscillating frequency andits amplitude. Analysis of the boiling heat transfer coefficientshow the increase for about 15% within the measured oscillatingfrequency range. As regard oscillating amplitude effect for therespective frequency of the heating surface oscillate, it wasshown that nonlinear dependency is obtained with increase of theamplitude. For higher frequency, amplitude effects on heattransfer coefficient is more pronounced. Using standardcorrelation method for pool boiling heat transfer a followingcorrelation is obtained : Nu = C(A,f) * Re exp(n1) * Pr exp(n2) * Kp exp(n3)
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration

  5. Type of paper: Paper in proceedings

    Title: Temperature Fluctuation of the Pool Boiling Heat Transfer in the Vicinity of the Oscillating Surface

    Authors:
    Žitko, Vinko (55624)
    Lučin, Davor
    Afgan, Naim
    Editors
    Srb, Neven
    Štefan, Stjepan
    Meden, Đorđo
    Tauschitz, Jozef
    Neumann, Gerd
    Dužević, Davor
    Trontelj, Marija
    Drofenik, Miha
    Turina, Tugomir
    Biljanović, Petar
    Benčić, Zvonimir
    Muljević, Vladimir
    Galić, Roman
    Lučin, Davor (190492)
    Proceedings title: Zbornik radova broj 1 sa 4. međunarodnog simpozija o novim tehnologijama
    Language: engleski
    Place: Zagreb
    Year: 1993
    Pages: from 133 to 139
    Meeting: 4. međunarodni simpozij o novim tehnologijama
    Held: from 10/25/93 to 10/27/93
    Summary: It is the main purpose of this resarch work to determine theoverheating of liquid in relation to vapour in bubbles washed bythis liquid. This process takes place at water pool boiling atatmospheric pressure. A specially designed microthermocouple tomeasure water temperature fluctuations at distances 0.5, 1.5,2.5, 3.5, 4.5, 5.5 * 10 exp(-3) m from the heating surface.Measurements were performed both at the nonvibrating andvibrating state. The following parameters were applied: amplitudeof 1 * 10 exp(-3) m, frequency of 40 Hz and heat flux of 31.7*10 exp(4) W/m2. The computer program for computing the requiredoverheating by applying the logged data was written. It enablesthe calculation of overheating applying the measured temperaturefluctuations for every position of the microthermocouple.Processing these data it can be concluded that in both vibrationstates (vibrating and nonvibrating) overheating increases bycoming nearer to the heating surface. Overheating at appliedvibration treatment is higher than without vibrations at greaterdistances from the heating surface. Coming nearer the heatingsurface this relation becomes evidently opposite. This researchwork was performed in Naval Institute in Zagreb and in theLaboratory for thermodinamic measurements at the Faculty ofElectrical Engineering, Mechanical Engineering and NavalArchitecture in Split.
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration, Temperature Fluctuations

  6. Type of paper: Paper in proceedings

    Title: Boiling Heat Transfer of Binary Mixtures from the Oscillating Heating Surface

    Authors:
    Žitko, Vinko (55624)
    Afgan, Naim
    Proceedings title: Proceedings of the 10th International Heat Transfer Conference
    Language: engleski
    Place: Brighton, Velika Britanija
    Year: 1994
    Meeting: Tenth International Heat Transfer Conference
    Held: from 08/14/94 to 08/18/94
    Summary: It is known that boiling heat transfer of the binary mixture isdependent on the concentration difference between liquid andvapor phase. It was also proved that the bubble departurediameter is a function of the binary component concentration.Recent investigation of boiling heat transfer of single componentfluid from the oscillating heating surface has shown dependencyof the boiling heat transfer coefficient on the frequency andamplitude of the surface oscillation. This paper deals with theinvestigation of the effect of concentration difference betweenliquid and vapor on the boiling heat transfer from theoscillating surface. It was our purpose to determine the genericmechanism which causes this effect and its relevancy to theboundary layer structure. Paper describes the measurementtechniques and apparatus and presents the obtained boiling heattransfer results for the water - ethylalcohol mixture. As anumber of modern apparatus are using binary mixture boiling heattransfer, it is of interest to observe the effect of theoscillating surface on the boiling heat transfer coefficient.Since some of the heat exchangers are working under conditionswith oscillating surfaces with liquid mixture, this investigationmay prove that there are limitations which are to be taken intoconsideration.
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration

  7. Type of paper: Paper in proceedings

    Title: Experimental Equipment for Measuring Boiling Heat Transfer from Horizontally Oscillating Surface

    Authors:
    Žitko, Vinko (55624)
    Lučin, Davor
    Jelaska, Damir
    Editors
    Balestrin, P.
    Bartak, G.F.
    Biljanović, Petar
    Dužević, Davor
    Feretić, Danilo
    Kelemen, T.
    Markovčić, Nada
    Mikuličić, V.
    Muljević, Vladimir
    Peruško, U.
    Srb, Neven
    Šurina, T.
    Vranješ, B.
    Proceedings title: Proceedings of the 5th International Simposium on New Technologies
    Language: engleski
    Place: Zagreb
    Year: 1995
    ISBN/ISSN: 953-6228-00-9
    Pages: from 119 to 123
    Meeting: 5. međunarodni simpozij o novim tehnologijama
    Held: from 09/25/95 to 09/27/95
    Summary: The paper deals with the structure of experimental equipment the purpose of which is to carry on the research of the influence of horizontal oscillations of the horizontal heating surface on heat transfer coefficient at pool boiling, as well as the fundamental experimental research of the pool boiling heat transfer in these conditions. For the applied heat flux and vibration parameters the coefficients of heat transfer from the horizontal heating surface to water are given. Analyzing the results of the preliminary measurements, the improvement of the heat transfer coefficient of up to 30 % in relation to nonvibrating state can be noticed.
    Keywords: Pool Boiling with Vibrations, Horizontally Oscillating Surface, Boiling Heat Transfer, Microthermocouple

  8. Type of paper: Paper in proceedings

    Title: Boiling Heat Transfer from Horizontally Oscillating Surface

    Authors:
    Žitko, Vinko (55624)
    Afgan, Naim
    Proceedings title: Proceedings of the 2nd Europian Thermal Sc.& 14th UIT Nat. Heat Transfer Conf.
    Language: engleski
    Place: Rim, Italija
    Year: 1995
    Meeting: 2nd Europian Thermal Sciences & 14th UIT National Heat Transfer Conference
    Summary: The paper describes the fundamental experimental research of the pool boiling heat transfer, occurring during the horizontal vibration of the heating surface. The advanced water pool boiling from the horizontal heating surface occurring at atmospheric pressure is performed with an equipment made specifically for this purpose. For the applied heat flux and vibration parameters the coefficients of heat transfer from the horizontal heating surface to water are given. Analyzing the results of the preliminary measurements, the improvement of the heat transfer coefficient of up to 30 % in relation to nonvibrating state can be noticed
    Keywords: Pool Boiling with Vibrations, Horizontally Oscillating Surface, Boiling Heat Transfer, Microthermocouple

  9. Type of paper: Paper in proceedings

    Title: Enhanced Pool Boiling Heat Transfer

    Authors:
    Žitko, Vinko (55624)
    Language: hrvatski
    Year: 1994
    Meeting: In memoriam Fran Bošnjaković
    Held: from 10/25/94 to 10/25/94
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibrations, Temperature Fluctuations

  10. Type of paper: Paper in proceedings

    Title: Temperature Fluctuation in Boundary Layer Induced by Surface Oscillation

    Authors:
    Žitko, Vinko (55624)
    Afgan, Naim
    Proceedings title: Atti del XII Congresso Nazionale sulla Trasmissione del Calore
    Language: engleski
    Place: L'Aquila, Italija
    Year: 1994
    Pages: from 275 to 286
    Meeting: XII Congresso Nazionale sulla Trasmissione del Calore
    Held: from 06/23/94 to 06/24/94
    Summary: Heat transfer surface vibration in boiling liquid is used to induce additional turbulence in the liquid in the vicinity of heated wall. Experimental investigation of the vibration parameters effect on the temperature fluctuation is studying in order to obtain insight in the mechanism of the heat transfer by induced vibration. Particular attention was focused to the analysis of the temperature fluctuation parameters and its relation to the heat transfer intensification. In this respect, it was aimed to study fundamental notion about possibility to reach resonance frequency and increase heat transfer performance. Temperature fluctuation was measured in the boiling two phase boundary layer for water and ethyl alcohol boiling in the range of the heat flux q = 5 - 30 W/cm2. Temperature measurement was performed with the microthermocouple diameter d = 30 Šm and its cot of frequency f = 140 Hz. Thermocouple signal was obtained for different distance from the heated wall included r = 0.5, 1.5, 2.5, 3.5, 4.5, 5.5 mm. Measurements is performed at oscillating parameters defined by its amplitude A = 1 mm and frequency f = 40 Hz. Special attention was focused to the measurement in the water - ethylalcohol mixtures. Measurement is performed at the atmospheric pressure at respective saturation condition. Data processing is obtained by respective amplitude and frequency analysis of the thermocouple signal including probability distribution of the signal and its autocorreltion for each position of the thermocouple. Results obtained prove that induced oscillation of the liquid temperature in the two phase boundary layer are closely correlated to the respective increase of the heat transfer from the oscillating surface. Due to the limited oscillation frequency range in this experiment there was not able to notice any resonant frequency effect as a result of the induced temperature fluctuation induced by heat transfer surface oscillation.
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration, Temperature Fluctuations

  11. Type of paper: Ph.D.

    Title:
    Faculty: Fakultet strojarstva i brodogradnje Sveučilište u Zagrebu
    Date of defense: 04/29/95
    Language: hrvatski
    Number of pages: 244
    Summary: The experimental research of mechanism, intensity and structure of the two-phase liquid-vapor system occuring while inducing the heated surface oscillation is performed. A particular attention is paid to the study of the influence of induced oscillations of the heating surface on fluctuation of parameters in the vicinity of interstage area. Experimental research of heat and mass transfer phenomena in the vicinity of interstage area are provided using heat flux up to 60.104 W/m2, amplitude up to 0,002 m and frequency up to 70 Hz. The parameter analysis of the influence of the heating surface oscillations on heat transfer coefficient using pure components and their mixtures aims at creating the basis for improved design of the engineering systems where the problems of heat area vibrations can lead to hazardous situations.
    Keywords: Heat Transfer, Pool Boiling, Binary Mixtures, Boiling with Vibrations


  12. Type of paper: M.A.

    Title:
    Faculty: Fakultet strojarstva i brodogradnje Sveučilište u Zagrebu
    Author: LUČIN DAVOR
    Language: hrvatski
    Number of pages: 176


  13. Type of paper: TV broadcast

    Title: Water Boiling

    Authors:
    Žitko, Vinko (55624)
    Lučin, Davor
    Govedić, Stanko
    TV station: Hrvatska radio - televizija
    Name of emission (broadcast): Znanost i mi
    Year: 1993
    Language: hrvatski
    Summary: In a popular form for television spectators the complete cyclus of the experimental work on theme "Heat Transfer of Binary Mixtures at Boiling from Vibrating Surface" was presented. The program shows the experimental apparatus designed for thatpurpose. The filming was done in Naval Institute in Zagreb during the applying of their equipment for vibration technique. The aim of the presented work is to find out the most favorable solution i.e. to determine the best thermodynamic and vibration parameters for increase of the boiling heat transfer applying the heating surface vibrations. The presented contents is a part of the project P:2-08-204 theme and it was presented for television spectators in September 1993..
    Keywords: Heat Transfer, Pool Boiling, Boiling with Vibration


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