Design Enhancements of a High Temperature, Ceramic Micro-Channel Heat Exchanger

The recent developments in the energy and process industries have lead to more efficient, higher-temperature processes and compact equipment. By using small features such as micro-channels, pin fins or plate fins the length scale for which transport occurs is minimized and thus increases the heat transfer. By integrating high-thermal conductivity ceramic foams into these compact heat exchanger designs, even greater benefits of reduced hydraulic diameters and increased surface areas can be realized in environmentally durable, structurally strong materials. In this paper we will discuss several design configurations coupled with the inherent properties of preferred ceramic materials to assess the effects of foam pore size and overall porosity. These foams have been laminated into micro-channel assemblies and co-fired into monolithic devices for operational testing. The interfacial thermal-contact resistances between the porous foams and the dense films were eliminated by a co-firing process. Within these studies hydrodynamic and heat transfer models were used to predict the performance and viability of next generation high temperature heat exchangers.