ANALYSIS OFVIBRATORY STRESS OF INTEGRAL SHROUD BLADE FOR MECHANICAL DRIVE STEAMTURBINE by Yasutomo Kaneko
The advanced integral shroud blade (ISB) structure has been developed to improve the reliability and thermal efficiency of mechanical drive steam turbines. This advanced ISB has been applied to not only the control stage blades but also the intermediate stage blades. Turbines using these advanced blades have been successfully operated. This paper presents the analysis method to calculate the vibratory stresses of the ISB caused by the stage interaction force and the shock load. The vibration response characteristics are explained and comparisons are made to the advanced ISB structure and the conventional grouped blade structure, using the calculated results. Additional verification test results to confirm the validity of the proposed analysis method are also shown.
Turbine blade vibration due to partial admission
Abstract A method is given for analyzing the vibrations of turbine blades during partial admission. The combined effects of shock loading as the blades enter and leave the arc of admission, and nozzle wake loading in the arc of admission are included. By separating these two effects, the dependence of blade stress on natural frequencies, running speed, number of nozzles, number of blades per row, number of blades per group and damping is illustrated. Apparatus for determining experimentally the exact nature of the steam loading acting on the blades is described.
Hydrogen-rich gas production from biomass air and oxygen/steam gasification in a downdraft gasifier
Biomass gasification is an important method to obtain renewable hydrogen. However, this technology still stagnates in a laboratory scale because of its high-energy consumption. In order to get maximum hydrogen yield and decrease energy consumption, this study applies a self-heated downdraft gasifier as the reactor and uses char as the catalyst to study the characteristics of hydrogen production from biomass gasification. Air and oxygen/steam are utilized as the gasifying agents. The experimental results indicate that compared to biomass air gasification, biomass oxygen/steam gasification improves hydrogen yield depending on the volume of downdraft gasifier, and also nearly doubles the heating value of fuel gas. The maximum lower heating value of fuel gas reaches 11.11MJ/Nm3 for biomass oxygen/steam gasification. Over the ranges of operating conditions examined, the maximum hydrogen yield reaches 45.16gH2/kg biomass. For biomass oxygen/steam gasification, the content of H2 and CO reaches 63.27–72.56%, while the content of H2 and CO gets to 52.19–63.31% for biomass air gasification. The ratio of H2/CO for biomass oxygen/steam gasification reaches 0.70–0.90, which is lower than that of biomass air gasification, 1.06–1.27. The experimental and comparison results prove that biomass oxygen/steam gasification in a downdraft gasifier is an effective, relatively low energy consumption technology for hydrogen-rich gas production.