HEAT EXCHANGER WITH MULTI-ZONE HEAT TRANSFER SURFACE

A heat exchanger with a multi-zone heat transfer surface is disclosed. The heat exchanger includes a fluid flow passage extending between and interconnecting a fluid inlet and a fluid outlet. A heat transfer surface is disposed within the fluid flow passage wherein the heat transfer surface includes at least one heat transfer-reducing zone disposed in thermal contact with a portion of at least one of the walls of the fluid flow passage and at least one heat transfer-augmenting zone disposed in thermal contact with a portion of the at least one of the walls of the fluid flow passage. The configuration of the heat transfer-augmenting zones with the heat-transfer-reducing zones is such that heat transfer across the surface of the heat exchanger in contact with the heat transfer-augmenting zones is increased relative to the heat transfer across the surface of the heat exchanger in contact with the heat transfer-reducing zones.