TITLE.PM5

838 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 where, ()Eλb = Monochromatic (single wavelength) emissive power of a bl ...

HEAT TRANSFER 839 dharm \M-therm\Th15-4.pm5 The plot shows that the following distinct characteristics of black body radiations ...

840 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 This law holds true for more real substances ; there is however some de ...

HEAT TRANSFER 841 dharm \M-therm\Th15-4.pm5 φ dA 1 dφ r sinθ θ r dθ rdθ r sin dθφ dA = r sin d d 2 2 θθ φ (b) Illustration for e ...

842 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 15.5.9.2. Lambert’s Cosine Law The law states that the total emissive p ...

HEAT TRANSFER 843 dharm \M-therm\Th15-4.pm5 = 5.67 × 5914 100 F^4 HG I KJ = 6.936 ×^10 (^7) W/m 2 Example 15.25. Calculate the f ...

844 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 solid angle at the centre of the other. Let dω 1 be subtended at dA 1 b ...

HEAT TRANSFER 845 dharm \M-therm\Th15-4.pm5 F1–2 is known as ‘configuration factor’ or ‘surface factor’ or ‘view factor’ between ...

846 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 (ii)When the body is not grey : Absorptivity when source is at 500°C = ...

HEAT TRANSFER 847 dharm \M-therm\Th15-4.pm5 = π π π ×××× − + ×× ×× L − NM O QP 0 022 1 5 67 10− 813 1373 1 062 0 022 018 1 082 1 ...

848 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 Fig. 15.54 In this case F1–2 = F2–3 = 1 ; and A A r r 1 2 1 2 5 10 == = ...

HEAT TRANSFER 849 dharm \M-therm\Th15-4.pm5 Rate of evaporation of liquid air : The heat flow from the inner sphere surface to o ...

850 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 Now substituting the values in the above equation, we get Q 12 = 0 283 ...

HEAT TRANSFER 851 dharm \M-therm\Th15-4.pm5 or TT TT 14 − (^34) = 34 − 24 27.33 25.25 or TT 14 −= 34 27.33TT 34 − 24 25.25 () = ...

852 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 dx = Thickness of body in the direction of flow, and k = Thermal conduc ...

HEAT TRANSFER 853 dharm \M-therm\Th15-4.pm5 The heat transfer is constant when (a) temperature remains constant with time (b) t ...

854 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 Theoretical Questions Enumerate the three modes by which heat can be t ...

HEAT TRANSFER 855 dharm \M-therm\Th15-4.pm5 Calculate the heat flowing through a furnace wall 0.23 m thick, the inside and outs ...

856 ENGINEERING THERMODYNAMICS dharm \M-therm\Th15-4.pm5 A spherical shaped vessel of 1.2 m diameter is 100 mm thick. Find the ...

16 Compressible Flow 16.1. Introduction. 16.2. Basic equations of compressible fluid flow. 16.3. Propagation of disturbances in ...