Improvement of heat transfer in tube-bundle heat exchangers by using structured tubes
Central Innovation Programme for medium-sized enterprises (ZIM), 20 October 2020 to 30 September 2023
The aim of the research project is to improve the energy efficiency and economy of gas-fired industrial furnace systems with central air preheating. This goal is to be achieved by increasing the surface area and improving the heat transfer of the individual tube bundles in a central recuperator. For this purpose, a process route for the production of structured tube bundles is to be developed based on processes for the material-preserving structuring of sheets. The introduction of a structure in various components has many advantages: Structured recuperator tubes have an increased efficiency compared to conventional smooth recuperator tubes due to the larger heat transferring surface. This leads to improved heat transfer. The structured tubes can be installed in both old and new systems without any special design effort. Due to the design, direct retrofitting in old systems to increase the efficiency is possible.
Figure of a simplified CFD model for the investigation of structured tubes in recuperators
Based on the structuring of the sheets, the investigation of the process steps suitable for series production for transforming the sheets into suitable tube bundles is carried out. These steps are supported by simulations of the fluidic, mechanical and thermal effects of the structuring depending on the structuring depth on the recuperator performance. An intermediate goal is the determination of the ideal structure dimensions and their production. The results obtained will be used to produce a demonstrator, which will initially be used in a test rig. Based on the data obtained, it will be possible to adapt the structure and the manufacturing method.
- Design of a structure with an increased heat transfer of at least 25%
- Implementation of a process route for the production of heat transfer increasing structures
- Successful structuring of small diameter tube bundles
- Successful integration of structured tube bundles into a recuperator system
- Conservation of resources through lower material usage due to higher bending stiffness
- Increase in efficiency or reduction of the installation space for recuperators by at least 25%
This project is funded by the Federal Ministry of Economic Affairs and Climate Action within the framework of the AiF project KK5123801RH0.