APPLICATION OF WATER EQUIVALENTS METHOD TO CALCULATION OF RADIATION RECUPERATORS WITH MICROFINNED SURFACE

Krzysztof Karczewski
2008 Metallurgy and Foundry Engineering  
NOTATION: α c -convection heat-transfer coefficient of furnace gas, W/(m 2 ⋅K) α -convection heat-transfer coefficient (microfinned element), W/(m 2 ⋅K) α g -heat-transfer coefficient of furnace gas, W/(m 2 ⋅K) c a -heat capacity of air, kJ/(m 3 ⋅K) c g -heat capacity of furnace gas, kJ/(m 3 ⋅K) D, d -equivalent diameter, m F -heating surface area, m 2 H -height of recuperator, m h -height of micro-fin, m l -distance between axes of micro-fines, m r -equivalent radius, m s -thickness, m k
more » ... hickness, m k -over-all heat-transfer coefficient, W/(m 2 ⋅K) Δp -pressure, Pa T g , t g -temperature of furnace gas, K, o C 40 T w , t w -wall temperature, K, o C T a , t a -temperature of air, K, o C Re -Reynolds Number N -Number of Heat Transfer Units Q -heat transfer rate, W q -heat flux, W/m 2 V -volumetric rate of fluid flow, m 3 /s W a -water equivalent of air, W/K W g -water equivalent of furnace gas, W/K w -velocity, m/s η -dynamic viscosity factor, (kg⋅m)/s λ -number of hydraulic resistance (microfinned element) ρ density, kg/m 3 Y -intensification function.
doi:10.7494/mafe.2008.34.1.39 fatcat:xzqldwym55aabg55maqqdg6mea