Gas turbine calculations for Ulstein Rolls-Royce

Terje I. Arvidsen, senior engineer with EPM Consultants, worked for a long time on the analysis and thermal calculations for the pressure turbine in the engine. Since then he has made similar calculations for other projects for Ulstein, which is now part of the Rolls-Royce Group.

Ulstein Rolls-Royce has developed a new type of combustion chamber which emits nitrogen oxide (Nox) at 1/10 in relation to conventional high-speed ferries.

"We made calculations of temperatures, pressure and wear and tear from different operational cycles," says Arvidsen. "These were used as a basis for operational calculations in order to find the correct intervals for service and maintenance."

The Ulstein turbine is a Eurodyn type engine, which has its origin in a Norwegian patent. It was first tested in Kongsberg in the 1980s and later developed by the Eureka project (EU 159) - a cooperative effort involving Turbomeca in France (50%), Ulstein Tubine in Bergen (30%) and Volvo Aerospace in Sweden (20%).

"This engine is special because it has a radial turbine. That is, hot gas from the combustion chamber enters the turbine wheel radially along the motor axis, not axially (the usual method). Compared with equivalent axially driven turbines, this motor is significantly more energy efficient," says Arvidsen.

The engine is compact and characterised by its light weight (2.6 tons). It is coupled directly to a water jet that drives the catamaran forward. Similar gas turbine motors have been tested on high-speed trains in Europe and have functioned well as power generators.

"A gas turbine is under development during its entire life thus continually requiring calculation revisions," says Arvidsen.