This experiment determined the validity of existing pool boiling curve models for spheres in nitrogen. We quenched copper, stainless steel and brass spheres of two different diameters in a pool of nitrogen. We created boiling curves comparing the temperature difference between the sphere surface and saturated nitrogen to the heat flux from the sphere. The curves were then compared to Rohsenow’s material dependent equation for nucleate boiling and other models to predict the minimum and maximum heat fluxes, independent of surface material. The relationship between heat flux and temperature change is different than the relationship found by Rohsenow, and is size and material dependent. We also found that maximum and minimum heat flux depends on material and radius. There is no correlation between thermal conductivity and heat transfer coefficient based on our findings; however, spheres with a larger diameter have larger maximum convection heat transfer coefficient. INTRODUCTION With knowledge of a pool boiling curve, it is possible to predict the amount of heat transfer induced by the boiling of a fluid. The level of heat transfer that can be obtained for engineering applications is highly dependent on the difference in temperature between the heating surface and the surrounding fluid. The shape of this curve is dependent on the shape of heating surface as well as the material properties of the heated surface and fluid. Both empirical constants and dimensionless numbers are used to form a boiling curve. Optimal operation conditions for an application can be predicted with the understanding of how different factors can shape the boiling curve [1]. Boiling curves are generally divided into four types of boiling: film, tra... ... middle of paper ... ...i, E.G., Smith, R.V., 1964, “Nucleate and Film Pool Boiling Design Correlations for O2, N2, H2, and He,” T-1, Plenum Press New York, K.D. Timmerhaus, eds., Cryogenic Engin. Conference, Boulder, pp. 325-341 [5] Borgnakke, C., Sonntag, R., 2008, “Fundamentals of Thermodynamics, 7th edition,” John Wiley & Sons, Inc., Hoboken. [6] Hensen, J., Abdullatif, E., “Fourier and Biot Numbers and the Accuracy of Conduction Modelling,” [7] Bevington, B.R. 1992, “Data Reduction and Error Analysis for the Physical Sciences”, McGraw Hill, NY [8] Freud, R., Harari, R., Sher, E., 2009, “Collapsing Criteria for Vapor Film around Solid Spheres as a Fundamental Stage Leading to Vapor Explosion,” Elsevier B.V., Nuclear Engin.and Design (239), pp. 722-727 [9] 2009, “CRC Handbook of Chemistry and Physics, 90th edition,” American Chemical Society CNC Press, Boca Raton, pp. 631-637
It was learned that changing the volume of the same substance will never change the boiling point of the substance. However having two different substances with the same volume will result in two different boiling points. The purpose of this lab was to determine if changing the volume of a substance will change the boiling point. This is useful to know in real life because if someone wanted to boil water to make pasta and did not know how much water to
The MCE is typically in the range of (1-5) k/T (in terms of the adiabatic temperature change). This modest change in temperature is obviously not sufficient for applications such as domestic refrigeration etc. [24].
Serway, Jewett. Physics for Scientists and Engineers 6th Edition. Pomona: California State Polytechnic University. 2004.
... middle of paper ... ... Brown, P., & Levinson, S. C. (1987).
The comparison between the vapour compression and vapour absorption systems are given in Table 1
Huis in ‘t Veld. E., Vingerhoets. E., & Denollet. J. (2011). Journal of Elsevier. 1099-1103.
... middle of paper ... ... 14 Nov 2011.. http://web.ebscohost.com/lrc/detail?vid=4&hid=110&sid=fef50b1c-4aba-40fd-83b1- 583a32991f55@sessionmgr110&bdata=JnNpdGU9bHJjLWxpdmU=> Edrich, Matthias. The.
on the rate of cooling of a globe of matter after first solidification occurs (
...he principle numbers of Froude, Reynolds and Weber. Mathematical model predicts the heat and mass transfer in numerical framework for both transports phenomena of relevance to the industry continuous casting tundish system. Additionally, it has an excellent agreement outlet temperature respond the step input temperatures in the inlet stream of water in the tundish model. The simulations of 8x8 grid and 16x16 grid are applied to obtain significant difference between the TAV maps in which both grids are computed by software represent the specific flow of the fluid in the model and the steel caster as the actual size system. Therefore, the physical and mathematical modeling is used as a guidance to build a model before the prototype is constructed in terms of calculation, measurement and determination of specific fluid flow, heat and mass transfer in the water model.
Serway, Raymond A, and Robert J Beichner. Physics: For Scientists and Engineers. United States of
(8) Gadamer, H.-G., Wahrheit und Methode, J.C.B. Mohr, Tübingen, 1990, p. 265 (hereafter quoted as WM and translated according to the English edition of G. Barden and J. Cumming; Seabury Press, 1975).
in chemical operations, minimization of building heat losses using improved insulation techniques, thermal control of space vehicles, heat treatment of metals, dispersion of atmospheric pollutants. A thermal system contains matter or substance and this substance may change by transformation or by exchange of mass with the surroundings. To perform a thermal analysis of a system, we need to use thermodynamics, which allows for quantitative description of the substance. This is done by defining the boundaries of the system, applying the conservation principles, and examining how the system participates in thermal energy exchange and
This is the transport of heat in a fluid by the motion of the fluid
In this present work the CFD simulation of heat sink is carried out for two different velocity magnitudes. The heat sink is modelled as a combination of Copper and Aluminium materials. The base of the heat sink is taken as Copper and the fins are modelled as Aluminium. A conjugate heat transfer analysis is carried out for this fluid – structure case. Two cases are simulated with a velocity of flow as 4 m/s and 10 m/s. The base of the heat sink is given with heat flux boundary. The results of both the scenarios are showing good coherence with the physical phenomenon. As velocity increases the temperature of the heat sink decreases, so the heat generated in the heat sink will become less. The rate of heat transfer will be
The science of heat transfer pursues not only to explain how heat energy may be transfer, but also to foresee the rate at which the exchange will take place under certain quantified conditions.