Critical conductivity ratio for conjugate heat transfer in eccentric annuli

Conjugate laminar forced convection heat transfer in the entry region of ec centric annuli is numerically investigated. Heat transfer parameters are pr esented for a fluid of Pr = 0.7 flowing in an annulus of radius ratio 0.5 f or four values of dimensionless eccentricity ranging from 0.1 to 0.7 Solid- fluid conductivity ratio (KR) is varied to cover the range for practical ca ses with commonly encountered inner and outer tube thickness. Boundary cond itions applied are isothermal heating of the inner surface of the core tube , while the outer surface of the external tube is maintained at the inlet f luid temperature. Limits for KR above which the conjugation can be neglecte d are obtained.