3 edition of Nucleate pool boiling of nitrogen from artificial cavities found in the catalog.
Pool boiling heat transfer of nitrogen from artifical cavities was investigated. Boiling was from circular, one inch diameter horizontal mirror finished copper plates. The single artifical cavity surfaces investigate were: a drilled 0.0043 inch diameter hole, a drilled 0.015 inch diameter hole, and 0.022 nich diameter spark cut cone, and an 0.006 inch diameter spark cut cylindrical hole. The multiple cavity surfaces investigated were: seven 0.015 inch diameter drilled holes, thirteen 0.015 diameter drilled holes, and ninety-seven 0.003 to 0.0045 inch diameter spark cut holes. The depth to diameter ration was about 2.5 for all drilled cavities. The data from a mirror finished surface was compared to that of previous investigations. Exponents for Yamagata"s Equation for boiling in the isolated bubble region were determined. The artificial cavities were found to affect the natural convection heat transfer. The size of the cavity appeared to have little effect after incipience of boiling, and larget cavities than previously expected were found to remain active.
|Statement||John Alfred Moulson|
|Contributions||Naval Postgraduate School (U.S.)|
|The Physical Object|
|Number of Pages||84|
Boiling is a key heat transfer process for a variety of power generation and thermal management technologies. We show that nanopillar arrays fabricated on a Cited by: Part of the Mathematical Engineering book series (MATHENGIN) Golobic I, Xing H et al () Mechanistic models for pool nucleate boiling heat transfer: input and validation. Heat Mass Concerning the influence of thermal properties of heating surface material on heat transfer intensity of nucleate pool boiling of liquids including Author: Yuri B. Zudin.
A simplified model for stability of nucleate pool boiling of liquid metals has been postulated from which the minimum heat flux for stable boiling can be found as a function of liquid-solid properties, liquid pressure, the degree of superheat, and the cavity radius and depth. Experimental tests with sodium boiling from horizontal sur-. Determines the heat flux and the convective heat transfer coefficient for a copper pipe where water is undergoing nucleate pool boiling. Made by .
The densities of the cavities were designed to be 33 × 33, 25 × 25 and 16 × 16 arrays with , and µm spacings, respectively. The characteristics of heat transfer for pool boiling of FC on artificial micro-cavity surfaces were also by: An experimental investigation of surface effects on nucleate pool boiling of liquid nitrogen from a horizontal surface. By Harold Wayne George. Download PDF (3 MB) Abstract. Approved for public release, distribution is effect of various surface conditions on the characteristic boiling curve for liquid nitrogen was experimentally Author: Harold Wayne George.
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Nucleate pool boiling of nitrogen from artificial cavities. Abstract. Approved for public release; distribution is unlimitedPool boiling heat transfer of nitrogen from artifical cavities was investigated. Boiling was from circular, one inch diameter horizontal mirror finished copper plates.
The artificial cavities were found to affect Author: John Alfred Moulson. A grease coating significantly decreases the nucleate-boiling heat-transfer coefficient. A Teflon coating has very little effect. Past history of the test surface, including the length of time spent while boiling, can change boiling results.
The effect of artificial cavities on both natural convection and nucleate-boiling was by: The onset of the pool-nucleate boiling was well predicted by the traditional pool-nucleate boiling theory. These results indicated that the artificial cavities behave just like natural cavities.
The results indicated the artificial more» cavities are quite useful and promising to examine the true features of complicated boiling that have been. The artificial-cavity heat transfer surface followed the pool-nucleate boiling trend. The onset of the pool-nucleate boiling was well predicted by the traditional pool-nucleate boiling theory.
These results indicated that the artificial cavities behave just like natural : Ryo Hateruma, Takato Sato, Yasuo Koizumi, Hiroyasu Ohtake. In this experimental study, fluorinert FC is boiled on a silicon chip with artificial cavities and integrated microsensors.
The horizontal silicon chip with dimensions of × 19 × mm is completely immersed in FC The integrated nickel–titanium temperature microsensors on the back of the chip are calibrated individually and exhibit a near-linear increase of electrical resistance with by: Results indicated that, in general, increasing the number of micro cavities also increase the enhanced surface area and it could increase the critical heat flux.
The pronounced increase of boiling heat transfer coefficients with the application of the artificial micro-cavity to the heat surface were also investigated in this : C.
Yu, D. Lu, T. Cheng, B. Tsai. Recent experiments on pool boiling on a flat plate were also conducted in the Boiling eXperimental Facility (BFX) aboard the International Space Station by Warrier et al.
on an aluminium wafer with five artificial nucleation cavities. Several local heaters and thermistors were Cited by: Nucleate boiling heat transfer (NBHT) from enhanced structures is an effective way to dissipate high heat flux.
In the present study, the cavities behaviours for nucleation on roughened surface. Effects of cavity size, shape, and their population on nucleation characteristics of a surface were investigated. A theoretical model has been developed for the stability of a cylindrical cavity in boiling considering the wetting characteristics of the fluid and the transient inertial, viscous, and Cited by: A mathematical model has been developed for heat exchange in nucleate boiling at high flux applying an energy balance on a macrolayer.
The wall superheat, macrolayer thickness, and time are the parameters considered for predicting the heat flux. The influence of the wall superheat and macrolayer thickness on average heat flux has been : Mohd Danish, Mohammed K.
Al Mesfer. Journal of NUCLEAR SCIENCE and TECHNOLOGY, 18[7), pp. (July ). Pool-Boiling Heat Transfer in Liquid Nitrogen* Muneo KIDA, Yoshihiro KIKUCHI, Usamu TAKAHASHI and Itaru MICHIYOSHI Department of Nuclear Engineering, Kyoto University** Received Decem An experimental study was conducted on pool-boiling heat transfer from an electrically.
Probably due to the removal of all permanent gas, the cavities generally became inactive after a series of experiments.
Figure 2. Three subsequent pictures of static bubble departure in water at two different artificial cavities, p = bar.
R(50 #m) = mm, R(25/~m) = mm. The Cited by: Abstract. Heat transfer to boiling liquids is a form of heat transfer with change of phase. The appearance of a second phase greatly complicates the mechanism of heat transfer, and it is not surprising that the study of boiling liquids is still the least developed phase of all forms of heat by: A simplified model for stability of nucleate pool boiling of liquid metals is postulated from which the minimum heat flux for stable boiling can be found as a function of liquid-solid properties, liquid pressure, the degree of superheat, and the cavity radius and by: The inclination angles were 5°, 30°, 45°, 60°, and 90° (vertical), the artificial cavities were cylinders with diameters of mm, mm, and 1 mm and depths of 1 mm and 2 mm and center-to-center spacings of 8 mm, 4 mm, and 2 mm.
The results show that the CHF increases as the inclination angle by: 9. The heat transfer coefficient (HTC) comparative analysis conducted at the heat flux of kW/m 2 exhibits the highest enhancement of % during nucleate boiling on the silicon sample with etched nucleation cavities with a 30 µm diameter and a mm pitch.
The experimental results consistently show that HTC increases with decreasing the pitch and increasing the size of the nucleation cavities Cited by: 1.
Both pool boiling and flow boiling are restricted in the nucleate boiling region by two factors: boiling hysteresis and critical heat flux (CHF).
Therefore, how to reduce the boiling incipience temperature and increase the CHF value is an important issue for extending the limitation of boiling heat transfer technology in the electronic cooling Cited by: Saturated pool boiling heat transfer rates were measured from downward facing and inclined surfaces with artificial cavities to study the effects of inclination angle and cavity structures on the.
An experimental investigation of surface effects on nucleate pool boiling of liquid nitrogen from a horizontal surface George, Harold Wayne Monterey, California.
U.S. Naval Postgraduate School etchedsurfaces,andsurfaceswithinchdiameterartificial cylindricalcavities. Nucleation site interaction in pool boiling on the artificial surface Article in International Journal of Heat and Mass Transfer 46(3) January with 40 Reads How we measure 'reads'.
The experiment of pool nucleate boiling of water was performed on a heated silicon surface with triple artificial cavities. The existence and the significance of three effect factors, the bubble. During the period of March–Maya series of boiling experiments was carried out in the Boiling Experimental Facility (BXF) located in the Microgravity Science Glovebox (MSG) of the International Space Station (ISS).
The BXF Facility was carried to ISS on Space Shuttle Mission STS– on Febru Nucleate Pool Boiling Experiment (NPBX) was one of the two Cited by: Pool boiling heat transfer on artificial micro-cavity surfaces in dielectric fluid FC October Journal of Micromechanics and Microengineering 16(10)