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.
Forced Response Prediction of Gas Turbine Rotor Blades

 An analytical forced response prediction system is used to predict turbomachinery airfoil vibratory stress amplitudes. The forced airfoil vibration can be caused by time dependent (unsteady) aerodynamic loads due to interaction with the flow field from neighboring airfoils rows, such as shocks, wakes, or pressure waves, or due to self induced unsteady aerodynamics such as vortex shedding and unsteady tip vortices. The amplitude of the forced response is of particular interest when the frequency of the time dependent unsteadiness is close to the natural frequency of the forced airfoil. At this condition, the airfoil is at or near resonance and vibratory stress can exceed the material capability causing high cycle fatigue (HCF) failures.
 The airfoil forced response prediction system presented here combines structural static and dynamic analysis with steady and unsteady computational fluid dynamic analysis in an iterative coupled solution to the aeroelastic problem. The system includes three dimensional viscous multistage steady and unsteady computational fluid dynamics and three dimensional geometric nonlinear structural static, linear free vibration and modal forced response analysis to predict the airfoil amplitude in the resonance modes during engine operation.
 This analysis system is being used to help identify the cause of HCF failure and determine corrective action. The analysis system is demonstrated using a compressor rotor excited by upstream and downstream vanes. Results are then compared with engine test data.
Study of Biogas for Power Generation at Pesantren Saung Balong Al-Barokah, Majalengka, West Java
Utilization of biogas from cow manure as a fuel alternative for power plants is done through an anaerobic process. A pilot plant with biogas production of 7 m 3 /day has been installed at Pesantren Saung Balong. Biogas is used for everyday purposes such as cooking and lighting, and used as pure biogas with 2.500 Watt scale generator. Biogas produced with the rate of 0.080 m 3 /hr. Biogas produced during the measurement (450 minutes) is 0.604 m 3 . With these data it is predicted that within a day (24 hours) biogas which can be generated is equal to 1.92 m 3 . Meanwhile, consumption of biogas to the generator with 1.047 W load is 0.019 m3/minutes, the generator will operate for approximately 101.05 minutes or 1.68 hours. Thus electricity that can be saved is 1.759 kWh per day or 52.77 kWh per month and electricity cost that can be saved that is equal to Rp.40.896/month.