A rotary ceramic regenerator is the most efficient high temperature heat exchanger being considered for the automotive gas turbine application. Under the HVTE-TS program sponsored by the U.S. Department of Energy, our activities have focused on the identification and development of materials and on the development of hardware required for the extrusion of this product.
Initially, five ceramic materials were identified which showed promise for meeting the performance criteria of the product. Of these five, lithium-aluminosilicate (LAS) glass and magnesium-aluminosilicate (MAS) ceramic batches were chosen.
MAS materials had been developed for use in automotive catalyst supports and so have cost and processing advantages for automotive applications. Cellular MAS parts have been extruded, fired, finished, and supplied to Allison Engine Company for testing.
LAS products have been in use for many years in gas turbine regenerators throughout the world. This product, however, is unacceptably expensive for the automotive application. Several different lines of inquiry are being pursued to address the cost of the present LAS batch.
To provide a wider processing window than that available using the current hardware, new automotive extrusion die manufacturing ideas are being evaluated.
This paper will discuss the status of the materials and hardware developments, including the status of regenerator testing.