Evaporation Condensation and Heat transfer Part 8 pptx

spsi mc  si si w i si si si TNTNTiN N ⎡⎤ ⎛⎞ ⎢⎥ ⎜⎟ ⎜⎟ ⎢⎥ ⎝⎠ ⎣⎦ x xL N L x gi gi TT gi gi gpg g i gpg g ioz g wi TT mc T mc T r xh T ⎛⎞ ⎜⎟ ⎜⎟ ⎝⎠  gi gi gpg i g i g iz g wi TT mc T T Ah T ⎛⎞ ⎜⎟ ⎜⎟ ⎝⎠  zoz Ar x pg g i pg g i pg i cT cT c g i gpg i g z g i g zw i gpgi g z TmchAThAT mc h A ⎡ ⎤ ⎛⎞ ⎢ ⎥ ⎜⎟ ⎝⎠ ⎣ ⎦   gz gz gi gpgi gpggi pggi hA hA N mc mc T c T ⎡ ⎤ ⎢ ⎥ ⎣ ⎦   g pg i mc  gi gi w i gi gi gi TNTNTiN N ⎡⎤ ⎛⎞ ⎢⎥ ⎜⎟ ⎜⎟ ⎢⎥ ⎝⎠ ⎣⎦ wwi wwi wi wi ssi wi in c w kT kT TT hT T d d si si cino inosi TT ddd rrT wwi wwi wi wi wi wi cz s wz kT kT TT TT dk d soz oz dd r wi wi ggi wi o z z s z TT hT T d k d wwi wwi c wi ssiin w w wwi wwi c sin w kT kT d ThTdT kT kT d hd ⎡ ⎤ ⎢ ⎥ ⎢ ⎥ ⎣ ⎦ wwi wwi cs wi wi z wi wz wwi wwi cz s wz kT kT dd TTkT kT kT dk d ⎡ ⎤ ⎢ ⎥ ⎢ ⎥ ⎣ ⎦ s wi g oz g iz wi z s go z z z d ThdTkT d hd k ⎡ ⎤ ⎢ ⎥ ⎡⎤ ⎣ ⎦ ⎢⎥ ⎣⎦ sinlet T g inlet T sinlet WP T ginlet PP I T I N 5. Convection and radiation heat transfer coefficients s h cg h g h rg h g cg rg hh h cg h cg s z g g Nu C C cg s z g g Nu C C c g c g oz g Nu h d k sz CC gg oz g wd g g g w ssst Nu C t C g w w rg g g w TT h TT ε g ε w g T w T g w gg w rg g gw TTTT h TT rg h g w e rg e g w TT as h as TT a s ew w s oz oz ss d sC d ⎛⎞ ⎜⎟ ⎜⎟ ⎝⎠ C C C C C C C 6. Example of superheater modeling o dm in dm ginlet TC sinlet TC s mkgs  g wms z m z kWmK w kTT k w s T s TK w TC w TC w TC wN TC wN TC wN TC 7. Conclusions F T Q  U A A F T ΔT lm ATlm QUAF T  8. Symbols a A in A o A c c p c F T h k x L m m  Q  r s 1 s 2 t T T T U U A in U o U w x, y, z x xxL yys 8.1 Greek symbols kc g m  T x y x y xN 8.2 Subscripts 9. References Wärmeübertragung in Dampferzeugern und Wärmetauschern Process heat transfer Evaporators, and Condensers Air-cooled Heat Exchangers and Cooling Towers Standard Methods of Thermal Design for Power Boilers Boilers for Power and Process Steam. Its Generation and Use Dynamics of Tube Heat Exchangers Archives of Thermodynamcs Heat Transfer Engineering [...]... VS 80 Pore diameter Strut Diameter Porosity Dp [µm] Sample ds [µm] ε 409 0.92 0.9 0 .87 0.91 0 .88 0 .89 0.95 0.94 0 .86 0 .89 0.9 0 .87 0.75 0 .89 0 .89 0 .89 0 .89 500 4429 400 569 83 1 184 0 2452 1500 4055 4449 3720 2 380 14200 4200 1 488 0 7440 186 0 930 88 120 255 337 224 152 366 232 189 1775 * 9 28 464 116 58 Specific surface Sp [m2/m3] 680 5600 5303 3614 16 58 1295 2000 7 58 6 68 791 1120 250 80 0 1 98 396 1 582 3164... 3164 Permeability Inertia coefficient K [m2] β [m-1] 1.38E-09 7.63E- 08 2.01E-09 2.11E-09 4.79E-09 1.14E- 08 3.62E- 08 7.20E- 08 8.95E- 08 1.30E-06 2.97E-07 6.60E- 08 2.00E-06 6 .83 E- 08 4 .80 E-06 1.30E-06 7.48E- 08 1 .89 E- 08 1 686 2 48 2175 1329 1 088 446 364 1107 180 111 266 389 350 2100 53 111 612 12 08 Table 1 Summary of various metal foam sample morphological and flow law properties Greyed values: Pore scale direct... lateral wall and adiabatic on the others Inlet temperature and pressure are imposed Other walls are symmetry planes Fig 5 Simulation of heat and mass transfer in a real metal foam : Both plane sections show velocity magnitude Solid matrix surface and streamlines are colored by respectively solid and fluid temperature ERG 20PPI (Hugo et al., 2010) 286 Evaporation, Condensation and Heat Transfer The... while the convective heat loss (Clausing, 1 981 ) is mainly determined by the receiver structure, wall temperature, and wind velocity The heat conduction loss (Zavoico, 2001) exists in cavity receiver through the insulation wall, and it can be ignored in many solar heat receivers 1 Corresponding author 304 Evaporation, Condensation and Heat Transfer In order to reduce the radiation heat loss, solar selective... promising and challenging technology for its high operating temperature and thermodynamic efficiency In solar thermal power plant (Odeh et al., 2003), the heat transfer medium in solar heat receiver is heated by concentrated solar radiation to some high temperature, and then it can be used to operate kinds of heat engine and generate electricity As a result, the heat receiver (Ortega et al., 20 08) is the... hold-up and heat transfer during single and two-phase flow through porous media International Journal of Heat and Fluid Flow 26, 156-172 Kanit, T., Galliet, S F I., Mounoury, V., Jeulin, D (2003) Determination of the size of the representative volume element for random composites: statistical and numerical approach International Journal of Solids and Structures, 40(13-14), 3647-3679 302 Evaporation, Condensation. .. along the main flow axis is not lower than 2.5mm for the 100PPI (Dp=500µm) and 2.5cm for the 10 PPI samples (Dp=5000µm) Fig 3 Experimental set-up for single-phase and adiabatic two-phase flow laws characterization (Bonnet et al., 20 08)  284 Evaporation, Condensation and Heat Transfer The test section (250 mm length, 50 mm wide and adjustable height) is instrumented with 12 pressure sensors (Sensym®,... authors propose global heat transfer coefficient of a channel filled by a porous media (Kim et al., 2001) There are few works dealing with local heat transfer coefficient between fluid and solid phase (Serret, Stamboul, & Topin, 2007) However wall heat transfer coefficient is an averaging on different transport and diffusion properties on a known channel or heat exchanger geometry and can thus be used... characteristics of solar heat receiver have been investigated in much literature (Cui et al., 20 08; Grena, 2010) In general, the heat losses from solar receiver mainly include three contributions: radiation heat loss, convective heat loss, and conduction heat loss The radiation heat loss (Melchior et al., 20 08; Li et al., 2010) is mainly dependent upon the receiver structure, wall temperature, and emissivity/absorptivity... the heat transfer coefficient is proportional to the heat flux in the studied boiling regime This indicates a stable behavior (no risk of burn-out) of any biphasic heat exchanger working in these conditions of heat and mass flux Fig 19 Boiling Curve: copper foam compared to sintered bronze fibers *: inserted; x: welded; stars: bronze fibers (Miscevic et al., 2002) 300 Evaporation, Condensation and Heat . ERG40 2 380 189 0.9 1120 6.60E- 08 389 Kelvin Cell 14200 1775 0 .87 250 2.00E-06 350 CTIF stoch. 4200 * 0.75 80 0 6 .83 E- 08 2100 VS 5 1 488 0 9 28 0 .89 1 98 4 .80 E-06 53 VS 10 7440 464 0 .89 396 1.30E-06. 1.38E-09 1 686 Ni10 4429 409 0.92 680 7.63E- 08 2 48 NC 4753 400 0.9 5600 2.01E-09 2175 NC 3743 569 88 0 .87 5303 2.11E-09 1329 NC 2733 83 1 120 0.91 3614 4.79E-09 1 088 NC 1723 184 0 255 0 .88 16 58. 16 58 1.14E- 08 446 NC 1116 2452 337 0 .89 1295 3.62E- 08 364 Cu 40 1500 224 0.95 2000 7.20E- 08 1107 Cu 10 4055 152 0.94 7 58 8.95E- 08 180 ERG10 4449 366 0 .86 6 68 1.30E-06 111 ERG20 3720 232 0 .89