This increased loss must be accurately estimated. To do so, annular cascade tests of the variable nozzles were performed. The relationship between the amount of clearance and the amount of loss, as well as changes in cascade loss resulting from changes in flow angle, were measured. Results of these tests are being incorporated into the variable power turbine.
5.6) Research for Marine Use
In addition to the above research, the following research into the unique problems associated with marine gas turbines is being carried out.
The various components will be subject to corrosion from the chloride in ocean water, and the turbine blades and other high-temperature components may be corroded by sulfur in the fuel. To prevent this, salt-water spray tests and high-temperature corrosion tests were carried out, and suitable materials and anti-corrosion coatings were evaluated.
The main cause of corrosion on the turbine blades and other high-temperature components is thought to be the deposition of Na2SO4 created when the sulfur contained in fuel mixes with the NaCl in sea salt. In high-temperature corrosion tests, the high-temperature gasses simulated to an actual gas have been used to evaluate the anti-corrosion performance of materials and coatings. The results of these tests are being incorporated into the SMGT (Figure 16).
In addition, when regenerative double-shaft gas turbines are used in ships, transient response to sudden load changes is important. Simulation models of the SMGT and propulsion systems have been made, and transient response characteristics under varying conditions are being studied.
Research is also being conducted on the SMGT's operating support systems and on troubleshooting systems, etc.
6. Conclusion
This concludes the overview of the SMGT and current research results.
At present, component research is in the final stage and progressing smoothly. The results of this research are being successively incorporated into a 2,500kW-class prototype gas turbine. During the rig tests scheduled for mid-2001, the performance of this prototype will be evaluated.
7. Acknowledgements
This research and development is being carried out with the support of the Ministry of Transport, the Association for Structural Improvement of the Shipbuilding Industry and the Nippon Foundation. The author wishes to express his thanks for their support.
The author also wishes to thank all persons involved for their enthusiastic guidance and support.
8. References
1) S&O Foundation; Committee Report, March 1993.
2) Sugimoto, T., et al., Proc. of IGTC '99 (1999), p100
