Αποτελέσματα Αναζήτησης
Algebraic expressions for the correction factor Fhave been developed for vari- ous shell-and-tube and cross-flow heat exchanger configurations [1–3], and the results may be represented graphically. Selected results are shown in Figures 11S.1 through 11S.4 for common heat exchanger configurations.
Heat Exchangers: ΔTLM = {(THo – TCo) - (THi – TCi)}/{ln[(THo – TCo)/ (THi – TCi)]} Parallel flow. Convection: q = hA(Ts - T∞) q = UA ΔTLM. ΔTLM = {(THo – TCi) - (THi – TCo)}/{ln[(THo – TCi)/ (THi – TCo)]} Counter flow. Radiation: qr = εAσT4 NTU = UA/Cmin Cr = Cmin/Cmax ε = q/qmax qmax = Cmin (THi – TCi) Diffusion equations:
4.0 – HEAT EXCHANGERS CALCULATIONS: The main basic Heat Exchanger equation is: Q = U x A x ΔT m = The log mean temperature difference ΔTm is: ΔT m = (T 1 – t 2) – (T 2 – t 1) = °F T 1 = Inlet tube side fluid temperature; t 2 = Outlet shell side fluid temperature; T 2 = Outlet tube side fluid temperature; t 1 = Inlet shell side fluid ...
Basic Thermodynamic Formulas (Exam Equation Sheet) Control Mass (no mass flow across system boundaries) Conservation of mass: 𝑚= 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐. Conservation of energy (1st Law): 𝑄−𝑊= ∆𝐸 = ∆𝑈+ ∆𝐾𝐸+ ∆𝑃𝐸 = 𝑚 ∆𝑢+ 𝑣2 2−𝑣 1 2 2 + 𝑔(𝑧2−𝑧1)
A heat exchanger is a component that allows the transfer of heat from one fluid (liquid or gas) to another fluid. Reasons for heat transfer include the following:
Heat Exchangers The rate of heat transfer associated with either stream in a heat exchanger in which incompressible fluid or ideal gas with con- Stant specific heats flows is Q = - where specific heat (at constant pressure) — mass flow rate The rate of heat transfer in a heat exchanger is Q - UAFATlm where any convenient reference area (m2)
EngineeringNotes.net 1 Heat Transfer Key Equations Heat Transfer Key Equations Here’s a hot nomenclature 𝑞 Power (heat transfer per unit time), measured in 𝑞′′ Heat flux (power per unit area), measured in 𝑚−2 Heat (thermal energy transferred over a time period), measured in 𝑘 Thermal conductivity (a material property), measured in 𝑚 −1
