question of heat transfer

... value of turbulent intensity is observed at the relative gap width of 1.0 which is in the line of heat transfer measurements. These results of PIV showed good agreement between the heat transfer ... Investigation of heat transfer and friction for rib- roughened surfaces, Int. Journal of Heat & Mass Transfer 1978; 21: 1143-1156. [4] Webb R.L., Eckert E.R.G. and Goldstein R. J. Heat transfer ... Journal of Heat and Mass Transfer1 999; 42: 1597-1615. [16] Karwa R, Experimental studies of augmented heat transfer and friction in asymmetrically heated rectangular ducts with ribs on the heated...

Ngày tải lên: 05/09/2013, 16:10

... A, and thickness of Fig. 2.2 can be stated as follows: rate of heat conduction rate of heat conduction into control volume out of control volume +=+ (2.1) rate of heat generation rate of energy storage ... Basic Modes of Heat Transfer 2 1.1 The Relation of Heat Transfer to Thermodynamics 3 1.2 Dimensions and Units 7 1.3 Heat Conduction 9 1.4 Convection 17 1.5 Radiation 21 1.6 Combined Heat Transfer ... Combined Heat Transfer Systems In the preceding sections the three basic mechanisms of heat transfer have been treated separately. In practice, however, heat is usually transferred by several of the basic...

Ngày tải lên: 08/04/2014, 11:00

... "m −0 K −0 #Ł L lv latent heat of evaporation ðJ kg −0 Ł L sl latent heat of fusion ðJ kg −0 Ł M molar weight ðkg kmol −0 Ł n ¼ complex index of refraction n\ k real and imaginary part of the complex index of refraction p ... instead of a Gaussian distribution commonly seen for other types of laser[ The size of the laser spot on the target surface is several millimeters\ while the heat di}usion depth is of the order of ... X[ Xu\ K[H[ Song\ Measurement of radiative properties of pulsed laser induced plasma\ J[ Heat Transfer 008 "0886# 491Ð497[ ð7Ł K[H[ Song\ X[ Xu\ Mechanisms of absorption in pulsed excimer...

Ngày tải lên: 06/05/2014, 08:55

... surface of the target by scaling velocities of atoms in cells on the top surface, and the same amount of heat flux is dissipated from the bottom of the target by scaling velocities of atoms ... Study of Light-to -heat Absorption Mechanism in atomic Systems," International Journal of Heat and Mass Transfer, 41, pp. 839-849. 3. Häkkinen, H., and Landman, U., 1993, "Superheating, ... the distribution of number density of atoms in space at different times, which demonstrates the variation of solid structure during laser heating. At the early stage of laser heating, the crystal...

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Ngày tải lên: 05/09/2013, 15:28

Ngày tải lên: 05/09/2013, 15:28

... types of latent heat. The first is the latent heat of fusion. This is the amount of heat added or removed to change phase between solid and liquid. The second type of latent heat is the latent heat ... ENERGY, WORK, AND HEAT Another type of heat is called latent heat. Latent heat is the amount of heat added to or removed from a substance to produce a change in phase. When latent heat is added, ... latent heat of vaporization. This is the amount of heat added or removed to change phase between liquid and vapor. The latent heat of vaporization is sometimes called the latent heat of condensation. Different...

Ngày tải lên: 17/03/2014, 15:00

... modes of heat transfer: Conduction involves the transfer of heat by the interactions of atoms or molecules of a material through which the heat is being transferred. Convection involves the transfer ... or molecules of a material through which the heat is being transferred. Convection involves the transfer of heat by the mixing and motion of macroscopic portions of a fluid. Radiation, or radiant heat transfer, ... HT-02 Heat Transfer Intentionally Left Blank HT-02 Page x Rev. 0 Heat Transfer TABLE OF CONTENTS TABLE OF CONTENTS LIST OF FIGURES iii LIST OF TABLES iv REFERENCES v OBJECTIVES vii HEAT TRANSFER...

Ngày tải lên: 17/03/2014, 15:00

... feet, of a column of water that a given pressure will support. Each of the energies possessed by a fluid can be expressed in terms of head. The elevation head represents the potential energy of ... represents the flow energy of a column of fluid whose weight is equivalent to the pressure of the fluid. The sum of the elevation head, velocity head, and pressure head of a fluid is called the ... Av • The principle of conservation of mass states that all mass flow rates into a control volume are equal to all mass flow rates out of the control volume plus the rate of change of mass within...

Ngày tải lên: 17/03/2014, 15:00

... boundary conditions of practi- cal interest. The number of excellent review articles, books and monographs, which summarise the state -of- the-art of convective heat and mass transfer, which are ... delaying the onset of the separation of the boundary-layer from the plate, as can be seen from Figure 2.15, where the plot of the location of the separation point, Xs, as a function of Pr (xs is ... interest and meaningful suggestions of Professor T Y. Na and Dr. D. A. S. Rees, the reviewers of this work. Secondly, the formatting of this book and the preparation of the figures were performed...

Ngày tải lên: 01/04/2014, 10:51

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Ngày tải lên: 02/04/2014, 15:24

... function of current for the range 100 Յ I Յ 5000 A. Also plot the ratio of the heat transfer by convection to the total heat transfer. 1.62 A small sphere of reference-grade iron with a specific heat ... applicability of heat exchanger analysis to heat sink design and materials processing. Much of the coverage of compact heat exchangers included in the previous edition was limited to a specific heat exchanger. ... depen- dence of the convection heat transfer coefficient h is generally weak. The surfaces of Figure 1.6 may also simultaneously transfer heat by convection to an adjoining gas. For the conditions of Figure...

Ngày tải lên: 02/04/2014, 15:51

... description of the heat transfer between a heat engine and its surroundings further limits the actual efficiency of a heat engine. 1.3.1 Relationship to the First Law of Thermodynamics (Conservation of ... heater dissipates 2 kW while submerged in a water flow that is at 20ЊC and provides a convection heat transfer coefficient of h ϭ 5000 W/m 2 ⅐ K. Neglecting heat transfer from the ends of the heater, ... 20-mm-thick sheet of the material is T 1 Ϫ T 2 ϭ 10ЊC. (a) What is the heat flux through a 2 m ϫ 2 m sheet of the insulation? (b) What is the rate of heat transfer through the sheet of insulation? 1.2 The heat...

Ngày tải lên: 02/04/2014, 15:51

... tot q/q ′′ vs. T, note that the convection heat transfer rate is always a small fraction of the total heat transfer. That is, radiation is the dominant mode of heat transfer. Note also that the convection ... generally small, concurrent heat transfer by radiation and/or conduction must often be considered. However, jet impingement is one of the more effective means of transferring heat by convection and ... Electrical heater is perfectly insulated from dryer wall, (3) Heater and switch are isothermal at T set , (4) Negligible heat transfer from sides of heater or switch, (5) Switch surface, A s , loses heat...

Ngày tải lên: 02/04/2014, 15:52

... 11:4 Mass and Heat Transfer ANALYSIS OF MASS CONTACTORS AND HEAT EXCHANGERS T. W. FRASER RUSSELL University of Delaware ANNE SKAJA ROBINSON University of Delaware NORMAN J. WAGNER University of Delaware v P1: ... 521 88670 3 December 21, 2007 23:45 68 Heat Exchanger Analysis Batch and semibatch heat exchangers are used when the heating or cooling of a fixed volume of fluid is required, whereas continuous ... entity. Each of these types of exchangers is discussed next. 3.3.1 Batch Heat Exchanger The batch heat exchanger system was discussed extensively in Subsection 3.2.3 with the development of methods...

Ngày tải lên: 02/04/2014, 15:52

... COMBINED MODES OF HEAT TRANSFER Previous sections treated each mode of heat transfer separately. But in practice all the three modes of heat transfer can occur simultaneously. Additionally heat generation ... Problem model. VED c-4\n-demo\demo1-1.pm5 12 FUNDAMENTALS OF HEAT AND MASS TRANSFER Solution: Refer equation 1.10 Heat convected + heat radiated = heat conducted considering 1m 2 , h(T 1 – T 2 ) + ... transfer Example 1.2: Determine the heat transfer by convection over a surface of 0.5 m 2 area if the surface is at 160°C and fluid is at 40°C. The value of convective heat transfer coefficient is 25 W/m 2 K....

Ngày tải lên: 08/04/2014, 10:55