The heat transfer p h e n o m e~ mociated with the laminar, conwant properties jlow of non-Newtonian Bingham &ids ouer sudden eqansions and through conhacfions in circular pipes are studied by numrrieaUy soluing the fully e8pric governing continuity, momenrum, ond energy equuiiom for a wide range of the gouerning Rey~lds, yield, and Pmndll numbers. The influonce of the yield number on the thmnnl/iPld is more pronaunced at high Reynolds and Pmndll numbers. I n the sudden -.on cacc this infLunce takes the form of a localized peak in the Nusselt number distribution dew-m of the reaaachement point. The magnitude of the peak Nusselt number increases with the Rey~lds, yield, and P r d l numbers. A sharp reduction in the Nusselt number ualues righl before the contradon plane is found to be more significant at high R e y~l d s and Pmndll numbers.