Power dense heat recuperation for aircraft engines
| Reference number | |
| Coordinator | GKN AEROSPACE SWEDEN AB - Avd 9005 |
| Funding from Vinnova | SEK 1 522 949 |
| Project duration | July 2013 - May 2017 |
| Status | Completed |
Purpose and goal
The purpose of the project is to develop turbofan engines for passenger aircraft with a reduced fuel consumption by recuperation of waste heat from the turbine exhaust. The goals are to develop a concept with a heat exchanger and a with the core engine integrated secondary heat engine with an air based Brayton cycle and to manufacture and test a heat exchangers aerodynamic performance. An Exhaust Heated Bleed engine was described in "High Power Density Work Extraction from Turbofan Exhaust Heat", ISABE-2015-20101. Tests of a heat exchanger validated the loss model used.
Expected results and effects
The results indicate that the engine would be 3-7% more efficient than a conventional turbofan, but that the weight and bulk of a heat exchanger for recovery of heat at low pressure would be large and bulky. The results gives an increased understanding of geometric and thermal aspects of heat exchanger integration, as well as constraints on design of a transonic turbine for the temperature range 300-500 C. With the experience from this project new engine concepts with recuperation have been proposed and are under development in projects with participation from Chalmers and GKN.
Planned approach and implementation
The performance of a turbofan with heat recovery was simulated. The engine’s thermodynamic cycle was used to generate requirements for the heat exchanger and heat recovery turbine in terms of temperature and flow. Geometries for two alternative turbines were generated at LTH and their mechanics and aerodynamics investigated. Roughly ten different designs of the heat exchanger were studied in cooperation between Ranotor, GKN and Chalmers. Based on one of these a section of a heat exchanger module was built in half scale (app. 500 x 500 x 32 mm) and tested at Chalmers.