The Technological Concept of a Self-Adjusting Segmented Ceramic Sealing System for a Turboshaft Engine with Isochoric Combustion

The article presents self-adjusting segmented ceramic seals designed for a novel turboshaft engine operating according to the Humphrey thermodynamic cycle. The sealing system is an integral part of the developed engine concept, which features rotating isochoric combustion chambers. The seals utilize centrifugal force as the sealing force, enabling uniform sealing regardless of thermal conditions and associated deformations. The sealing consists of segments with adjustable dimensions in both circumferential and transverse directions. The sealing elements should be made of Si₃N₄ ceramic, characterized by high thermal resistance (1300°C) and low thermal expansion (3.2•10⁻⁶/°C). The article presents three different variants of sealing systems, differing in terms of the technological possibilities of their manufacturing. Special treatments must be applied to ensure high machining accuracy of the sealing elements. The proposed sealing system is a critical point in the design of an engine with isochoric combustion chambers. Successful sealing is key to the implementation of the Humphreys thermodynamic cycle, which offers higher engine efficiency compared to classical turboshaft engines available on the market. The article concludes with the presentation of a model for experimental investigations, along with its thermal analysis.