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Process Engineering Equipment Handbook Episode 2 Part 7

Tham khảo tài liệu 'process engineering equipment handbook episode 2 part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | L-16 Life-Cycle Assessment FIG. L-8 Typical blade root-disc serration configuration. Source Liburdi Engineering. FIG. L-9 The cracks generally start inside on the bottom radius and are very difficult to detect in inspection. Source Liburdi Engineering. disastrous failures. This can be avoided and disc lives extended to 100 000 h by using performance-monitoring software to analyze changes to the disc cooling. Note that before this was done changing the disc material was tried but this did not work. The cracks persisted. The cracks were at the bottom of the fir tree and difficult to see. Note the following details from the figures Where cracks occurred Cracks along grain boundaries Root-disc gap configuration Compressor air and air hot-gas air paths are located at each disc root. Hot air accumulates where it shouldn t. Life-Cycle Assessment L-17 FIG. L-10 As found turbine disc cooling flows. Source Liburdi Engineering. TABLE L-3 Compare Measured and Predicted Values of Engine Parameters Source Liburdi Engineering Predicted Actual Increase combustor temperature 6.7-7.2 6.7 Increase exhaust temperature 2.2-3.9 1.1 Decrease compressor exit pressure 0.9 0.7 lb in2 kPa 6.2 4.8 Increase in fuel flow lb s kg s 0.011-0.019 0.016 0.005-0.009 0.007 Solution Feed cool air through diaphragms. No rotating components affected just the diaphragms. Rows 3 and 4 had compressor delivery air row 5 had intermediate stage compressor air from bleed valve. Diagram of cooling air distribution See Table L-3. Net effect on performance negligible 70-hp 52-kW increase 0.05 decrease in thermal efficiency 12 F 7 C increase in TIT 1 C 2 F increase in exhaust temperature 0.75-lb in2 5.2 kPa decrease in combustor shell Example case history 5. Power augmentation for a gas turbine in cogeneration service using steam injection. Operation of this system works best when Steam is injected only when a certain power is reached. All excess steam is injected and then the control system is allowed to vary IGVs