WE-NET Home Page/Summary of Annual Reports 1997

8.3 Development of turbine blades, rotors and other major components

8.3.1 R&D Goals

8.3.1.1 Research objective

As a part of the hydrogen utilization technology to get superior environmental performance and extremely high thermal efficiency, we conduct the surveys and technology developments of the main components of a hydrogen combustion turbine, and establish the basic technologies required for the development of a pilot plant.

8.3.1.2 Scope of Research

In this fiscal year, we performed turbine blades fabrication, basic test procedure for Tashiro test facility to three cooling systems selected in fiscal year 1996 results. And simultaneously the development of blades cooling technology, we conducted optimum design studies and element tests to ensure efficient cooling in high-temperature steam atmosphere in 1700°C.

For the development of rotor cooling technology, we conducted to collect basic data on seal mechanism techniques based upon model tests, and carry out thermo-fluid analysis between the rotor and disk and the sealing zone by computational fluid dynamics (CFD) in order to grade-up them design skill for it.

8.3.2 Results in fiscal year 1997

(1) Development of turbine blade cooling technology

Recovery/ internal cooling method(no steam blow)
1. Detailed design of test blades for cooling blades evaluation tests was conducted, and then tests blades were completed to fabricate them by precision casting procedure based upon the detailed design.
2. Connecting duct (instrument zone) and blades block were designed and related parts such as cooling line tubes and instrument devises were completed to detailed design as shown in Fig. 8-3-1.
Water cooling methods/water cooling for vanes and steam cooling for blades(small steam blow)
1. Detailed design of tests vane and blade for cooling evaluation tests was conducted, and then test vane and blade were completed to fabricate by precision casting based upon the detailed design.
2. In order to procedure for the fabrication of copper alloy vanes, several materials tests were conducted, and optimum thermal barrier coating (TBC), which coats on the vanes were selected.
3. Connecting duct (instrument zone) and blades block were designed and related parts such as cooling line tubes and instrument devises were completed to detailed design as shown in Fig. 8-3-2.
Hybrid cooling methods(film cooling and recovery internal steam cooling)
1. Film cooling efficiency tests were conducted and other laboratory tests such as tunnel flow tests devise and heat transfer characteristics tests were designed and fabricated.
2. Material characteristics for steam oxidation attack and mechanical property were confirmed and methods of TBC and fine holes manufacturing for film cooling were decided.
3. Detailed design of test blades for cooling blades evaluation tests was conducted, and then tests blades were completed to fabricate them by precision casting procedure based upon the detailed design.
4. Connecting duct (instrument zone) and blades block were designed and related parts such as cooling line tubes and instrument devises were completed to detailed design as shown in Fig. 8-3-3.
In fiscal year 1997, test conditions and test procedure including related items for cooling methods evaluation test scheduled in fiscal year 1998 were discussed by Japan power engineering and inspection corporation with discussion of three re-entrusted manufacturers. And then main component advisory committee conducted the review of evaluation items and process. (Refer to Fig. 8-3-4)
And HO radical materials generated in high temperature zone, which concerns steam oxidation attack to TBC, were studied.

(2) Development of turbine rotor cooling technology

In order to get rotor seal characteristics, improved CFD were checked to the results gotten in model tests by fiscal year of 1996,and parameters survey using data gotten from the experiment were conducted. Then seal shape and high performance seal mechanism was studied as referring in Fig. 8-3-5.

And a 50MW hydrogen combustion turbine rotor was studied in its basic design structural feasibility for first stage disks and optimum rotor disk cooling design.

Overall system flow balance were calculated and re-target of seal performance were proposed for highly seal efficiency.

8.3.3 Research plan for fiscal year 1998

Three cooling methods will be evaluated in evaluation test(condition : 1700°C, 2.5MPa) scheduled in fiscal year 1998 as its confirmation of feasible technology, and propose items concerned and basic idea for blades cooling development in the phase II plan. And improved CFD will be revised to establish its feasibility and also discussion items will be summarized in hydrogen combustion turbine rotor seal design.