3. (a) What is the physical interpretation of the Grashof number? (b) A glass-door firescreen, used to reduce exfiltration of room air through a chimney, has a height of 0.71 m and a width of 1.02 m and reaches a temperature of 232°C. If the room temperature is 23°C, estimate the convection heat rate from the fireplace to the room. (Assume air properties: k = 33.8 x103 W/mK, v = 26.4x106 m²/s, a. = 38.3x10-6 m²/s, Pr 0.69) %3D

3. (a) What is the physical interpretation of the Grashof number? (b) A glass-door firescreen, used to reduce exfiltration of room air through a chimney, has a height of 0.71 m and a width of 1.02 m and reaches a temperature of 232°C. If the room temperature is 23°C, estimate the convection heat rate from the fireplace to the room. (Assume air properties: k = 33.8 x103 W/mK, v = 26.4x106 m²/s, a. = 38.3x10-6 m²/s, Pr 0.69) %3D