Modern steam engines

The history of this project originates from SAAB Aerospace in the late 60’s. The company Ranotor has since carried on with the project. A steam engine within a Rankine steam cycle working with over-critical steam promise a very high efficiency at part load comparing to internal combustion engines. Further, there is of course great fuel flexibility and since the combustion is external one can reduce or completely eliminate a number of harmful and toxic emissions such as NOx. Waste heat recovery in for example truck engines is another area of application.

One focus of this project is to design and construct a functional prototype of a novel oil-free axial piston type steam expander. Apart from expanding steam, this could have applications such as AC-compressors, in ORC-cycles etc.

In 2007 the PhD student Rasmus Löfstrand Grip was employed at the department of Machine construction with the goal to research the mechanical behavior and to construct a functional prototype of the steam expander considered in this project. Since then there have been a number of student’s project focusing on different aspects of the project. For example; one student’s project have been to develop and construct an oil-free valve mechanism which the succeeded in with great success.

Publications:
Grip R. "Axial piston machine kinematics" OST 2007
Grip R. "Enabling tribological testing in a novel axial piston type steam expander" to be presented at NordDesign 2008
Platell P. "Displacement Expanders for Small-scale Cogeneration"
Platell P. "Novel steam engine for multi primary energy resources" Polygeneration & Technologies & Applications
Tarragona Spain October 16th-17th , 2007

Contact person: Rasmus Löfstrand Grip, grip@md.kth.se