methods of heat transfer conduction convection radiation

... Trang 1Proceedings of NHTC'01 35th National Heat Transfer Conference Anaheim, California, June 10-12, 2001 NHTC2001-20070 MOLECULAR DYNAMICS SIMULATION OF HEAT TRANSFER AND PHASE CHANGE ... with 160,000 atoms Heat conduction by the electron gas, which dominated heat transfer in metal, could not be predicted by the Morse potential function Alternatively, heat conduction was simulated ... the 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

Ngày tải lên: 06/05/2014, 08:55

... In this study the heat transfer coefficient of condenser and evaporator and the heat transfer limits were investigated The analytical heat transfer coefficient and the heat transfer limits and ... 5 shows the experimental data of Noie [10] for heat transfer coefficient of evaporator Figure 5 Heat transfer coefficient of evaporator versus average temperature of evaporator surface for different ... with small fill rates, Heat Recovery Systems,7(4), pp 319-327 [6] Busse, C.A., (1973) Theory of ultimate heat transfer limit of cylindrical heat pipes Int J Heat and Mass Transfer,16, pp 169-186

Ngày tải lên: 09/09/2015, 10:32

... LC are the rates of heat-transfer supplied by the heat source and released to the heat sink by the working fluid, respectively; Q H and Q L are the real rates of heat-supply and heat-release, respectively. ... Carnot heat engine of the same heat input, the generalized irreversible Carnot engine can deliver less power and release more heat to the heat sink. Hence, the rate of heat flow ( QLC ) to the heat ... irreversible Carnot heat engine cycle model Assuming the rates of the heat flow in the heat-exchangers follow the generalized radiative heat transfer law, q ∝ ∆(T n ) , where n is a heat transfer exponent,

Ngày tải lên: 09/09/2015, 10:32

... without the presence of the wall; they attributed this phenomena to the distortion of velocity field by the wall and consequent alteration of the heat transfer characteristics of the hot wire such ... electrically heated sensing probe The variation of heat loss from the thermal element can be interpreted as a measure of the fluid velocity changes There are two fundamentally different types of thermal ... response of the hot wire has enable the faithful measurement of fluctuating velocity in the typical range of frequency and amplitude encountered in a turbulent flow Trang 8C p Specific heat of fluid

Ngày tải lên: 16/09/2015, 17:14

... study of heat transfer and thermal performance with longitudinal fins of solar air heater Foued Chabane a,b,* , Noureddine Moummi a,b, Said Benramache a,c a Mechanical Department, Faculty of Technology, ... conventional flat-plate solar air heater has been investigated for heat transfer efficiency improvement by introducing forced convection[22,23], extend-ing heat transfer area [24,25] and increasing ... coefficient (W/m2K) Cp specific heat of air (J/kg K) Ac area of absorber plate surface (m2) i position of the thermocouple connected of 1–4 DT temperature difference (C) t time of the during day (h) Vf

Ngày tải lên: 13/01/2020, 11:50

... was observed in the critical values of ‘Jingxiu’, ‘Riesling’ and spine grape: heat injury of grapevines The comparison of investigation methods for heat injury of grapevines under Tc and OJIP test ... after 10 min of heat stress but rapidly decreased values than did‘Jingxiu’ Evaluation of heat tolerance in 47 cultivars (or species) of grapevine under Tc Generally, heat injury under heat temperature ... of Plant Resources and Beijing Key Laboratory of Grape Science and Enology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, People's Republic of China 4 Key Laboratory of

Ngày tải lên: 27/05/2020, 02:07

... radiative heat transfer equation The negative sign in the rate of heat transfer indicates that the sphere is gaining heat from the surrounding wall Trang 30Note that the rate of heat transfer by radiation ... same as the rate of heat transfer by conduction through the glass • This value for the convective heat transfer coefficient falls within the range given for the free convection of air in Table ... T = h c π D L (T p – T G) For steady state to exist the rate of heat transfer by convection must equal the rate of heat transfer by radiation TG = 101°C COMMENTS This example illustrates that

Ngày tải lên: 21/08/2020, 09:48

... rate of heat transfer by convection (Equation (1.10)) from the outer surface must be the same as the rate of heat transfer by conduction through the glass  This value for the convective heat transfer ... the conservation of energy require that the heat gain of the probe by radiation if equal to the heat lost by convection The rate of heat transfer by convection is given by Equation (1.10) q c ... For steady state to exist the rate of heat transfer by convection must equal the rate of heat transfer by radiation Trang 21PROBLEM 1.16 Water at a temperature of 77°C is to be evaporated slowly

Ngày tải lên: 21/08/2020, 13:29

... natural convection, the induced mass flow rate varied at 0.44 power of Grashof number The heat transferred to the working fluid via substrate heat conduction was found to account for 41–47% of the heat ... revised contributions, and it covers mainly (1) heat convection, (2) heat conduction, and (3) heat transfer analysis The first section introduces mixed convection studies on inclined channels, double ... thermal behavior of the ink, primer and paint, heating in biothermal systems, and RBF finite difference approach in heat conduction The third section includes heat transfer analysis of reinforced

Ngày tải lên: 19/06/2014, 10:20

... Incropera, Convection heat transfer in electronic equipment cooling, J.Heat Transfer 110 (1988) 1097–1111 [5] C K Cha and Y Jaluria, Recirculating mixed convection flow for energy extraction, Int j Heat ... ratio and more volume of cooling air is involved in cooling the heat source leading to better cooling effect • The direction of the motion of the lid also affects the heat transfer phenomena Aiding ... convection heat transfer in a lid-driven cavity, Int J Heat Mass Transfer 35 (1992) 1881–1892 [19] A.A Mohammad, R Viskanta, Laminar flow and heat transfer in Rayleigh–Benard convection with

Ngày tải lên: 19/06/2014, 10:20

... early stages of phase change simulations of metal like materials where the oscillatory “steady-state” develops 2.2 Porous media natural convection A variant of the test, where instead of the free ... However, this chapter is focused on one of the simplest classes of meshless methods in development today, the Radial Basis Function (Buhmann, 2000) Collocation Methods (RBFCM) (Šarler, 2007) The meshless ... Navier-Stokes equation is of the second order while the Darcy equation is of the first order and therefore different boundary conditions for the velocity apply Instead of the no-slip boundary condition

Ngày tải lên: 19/06/2014, 10:20

... 4(a) (b) (c) Fig 3 Geometry of domain with boundary conditions Trang 5In the considered problem one can take under consideration three types of heat transfer heat transfer coefficient, – thermal ... materials typically consist of stiff and strong material phase, often as fibres, held together by a binder of matrix material, often an organic polymer Matrix is soft and weak, and its direct ... stationary problem of heat transfer was solved using direct UMFPACK linear system solver The mesh structure depends on the number and positions of fibres and so the number of mesh elements was

Ngày tải lên: 19/06/2014, 10:20

... points of ageometry by requiring the balance of heat fluxes across the boundaries between neighbouringelements and the continuity of the temperature field, governed by the weak form of theheat conduction ... consequence of heat conduction to the substrate being themain mechanism of heat extraction from the interaction zone, a lower temperature gradient in the build direction slows down the heat flow, ... (b)Fig 10 (a) Evolution of the phase constitution of the material in the first layer (b)Distribution of properties along the wall height the intensity of the infra-red radiation emitted in the

Ngày tải lên: 19/06/2014, 10:20

... description and solution of heat transfer and phase change We analyze the problem of heat transfer in a 1D body during the melting and freezing process with an external heat flux or heat convection, which ... accumulation heatingFig 2 Schematic description of a heat accumulator using gravel Trang 5353 2.4 Utilizing the change of state in substances for the accumulation of heat A prospective method of heat ... model of heat accumulators The effectivity of transferring the heat to active elements in the accumulator consists in the optimum setting of dimensions and shapes in the process of circulation of

Ngày tải lên: 19/06/2014, 10:20

... As result, the transfer of heat, thermal gradient, flow of heat in the system and the cooling curves in different points of the system were simulated. Also, a mathematical model of optimization ... 343 and 423 K, as well as the loss of heat by convection on the external mold was fixed in 5, 70 and 150 W/m 2 .K. For the generation of heat, three models of the solid fraction were considered: ... Element Methods to Optimize by Factorial Design the Solidification of Cu-5wt%Zn Alloy in a Sand Mold 379 1.1 Mathematical solidification heat transfer model The mathematical formulation of heat

Ngày tải lên: 19/06/2014, 10:20

... 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

... 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 ... heat is transferred by convection and radiation in parallel. Hence, the rate of heat flow to the interior surface of the wall is the sum of the two heat flows (1.36) where T g = temperature of the ... specific heat c of the solid are all constant. The principle of conservation of energy for the control volume, surface area A, and thickness of Fig. 2.2 can be stated as follows: rate of heat conduction...

Ngày tải lên: 08/04/2014, 11:00