- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- Type of paper
: M.A.
Title:
Faculty: Fakultet strojarstva i brodogradnje Sveučilište u Zagrebu
Author: LUČIN DAVOR
Language: hrvatski
Number of pages: 176
- 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