Page 11 - Design and Operation of Heat Exchangers and their Networks

Nomenclature xv

δ thickness (m)
baffle-hole-to-tube clearance (m)
δ bt
fin thickness (m)
δ f
Kronecker symbol
δ ij
plate thickness (m)
δ p
shell-to-baffle clearance (m)
δ sb
shell-to-tube-bundle clearance (m)
δ st
tube wall thickness (m)
δ t
δ tp width of the pass divider lane in tube bundle (m)
ε dimensionless temperature change;
effectiveness;
energy balance error
ζ drag coefficient
η 0 overall fin efficiency
η el electric efficiency
η f fin efficiency
η p pump efficiency
λ thermal conductivity (W/mK)
μ dynamic viscosity (sPa)
μ f fin bypass efficiency
θ excess temperature (K);
angle of inclination;
dimensionless temperature
θ ctl upper central angle of baffle cut (rad)
central angle of baffle cut (rad)
θ ds
angle of louver strip (degrees)
θ s
Θ extended temperature vector (K or °C);
excess temperature vector, Θ ¼ T ^ T (K)
3
ρ density (m /kg)
σ ratio of free-flow area to frontal area
Δτ time delay in connecting pipe (s)
τ time (s)
φ penalty factor
φ v volumetric concentration
ϕ 2 two-phase multiplier
Φ dissipation function (s )
2
ψ area enlargement factor

Superscripts

T transpose
0
entrance or inlet
exit or outlet
00
initial steady state
– average parameters at new operating condition
– dimensionless variable
Laplace transform