This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Transient Conduction: The Lumped Capacitance Method Chapter Five Sections 5.1 thru 5.3 The Lumped Capacitance Method • Based on existence of a spatially uniform temperature distribution throughout the transient process, i.e., T ≈ fn (time only) • General Lumped Capacitance analysis: The text does a general case: which includes convection, radiation and/or an applied heat flux at specified surfaces as well as internal energy generation g surr r s r c s h s s E T T A h T T hA A q dt dT CV + = ∞ ) ( ) ( " , , , ρ We did the problem of Negligible Radiation and Source Terms The Solution is: where the thermal time constant is defined as The change in thermal energy stored for the transient process is Thermal Resistance, Rt Lumped Thermal Capacitance, Ct ) ( " , , ∞ = = = T T hA dt dT CV then q E h h s s g r ρ  =  = = ∞ ∞ t s i i t t CV hA T T T T τ ρ θ θ exp exp ) ( 1 CV hA s t ρ τ =  = = = = ∆ ∫ ∫ t i t s t stored t CV dt hA dt Q E τ θ ρ θ exp 1 ) ( E out The Biot Number and Validity of The Lumped Capacitance Method...
View
Full Document
 Spring '11
 CUDINA
 Thermodynamics, Convection, Heat, Heat Transfer, TI, capacitance method

Click to edit the document details