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Measurement of leakage in a novel all metal non-contacting annular seal at high temperature Alain Anderson Graduate Research Assistant Luis San Andrés.

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Presentation on theme: "Measurement of leakage in a novel all metal non-contacting annular seal at high temperature Alain Anderson Graduate Research Assistant Luis San Andrés."— Presentation transcript:

1 Measurement of leakage in a novel all metal non-contacting annular seal at high temperature Alain Anderson Graduate Research Assistant Luis San Andrés Mast-Childs Professor TRC project TRC 32513/15193S/ME START DATE: September 1, 2010

2 Trends in High Performance Turbomachinery Higher speeds & more compact units Extreme operating temperatures and pressures More efficient & reliable JUSTIFICATION Issues of Importance Reduce secondary flows (parasitic leakage) Reduce specific fuel consumption & COST Increase power delivery Eliminate potential for rotordynamic instability Source: GE Energy

3 TRC funded a two-year program -Conduct non-proprietary leakage tests with a HALO TM seal -Conduct leakage tests with a three tooth labyrinth seal for comparison OBJECTIVE Desired outcomes -Enable the application of state of the art sealing technology -Increase system efficiency -Reducing leakage -Eliminating wear of components -Extending maintenance intervals

4 PRIOR WORK [1] To measure leakage in three test seals by varying: Supply pressure (upstream) from 1 bar to 3.5 bar Air inlet temperature from 30ºC to 300ºC Rotor speed from 0 rpm to 3,000 rpm To estimate drag torque (power loss) from each seal Compare three seals and provide recommendations A power gas turbine OEM wished to benchmark novel seal types against a (traditional) labyrinth seal to realize benefits and to ensure potential gains

5 TEST SEALS [1] Labyrinth Seal Brush Seal Hybrid Brush Seal

6 EXPERIMENTAL FACILITY

7 Flow in (supply pressure) Flow out (ambient pressure) cm EXPERIMENTAL FACILITY Test seal

8 Maximum air pressure: 100 psig EXPERIMENTAL FACILITY Centering mechanism Test seal

9 a) Revamp test rig for operation at higher rotor speeds to reach a tip surface speed of 120 m/s (15 krpm). Thermal and centrifugal growth at high speeds is expected to further decrease leakage b) Perform clearance and leakage measurements with a three teeth labyrinth seal and the HALO TM seal operating with pressure ratios as high as 8, temperatures to 300ºC, and tip surface speeds to 120 m/s c) Compare the labyrinth seal measured leakage with XLLaby® predictions at high temperature. The benchmarking is essential to trust, modify or discard current predictive models Proposal to TRC (2 years) TRC members benefit from existing high temperature seal test rig

10 a) Revamp test rig for operation at higher rotor speeds to reach a tip surface speed of 120 m/s (15 krpm). Thermal and centrifugal growth at high speeds is expected to further decrease leakage b) Perform clearance and leakage measurements with a three teeth labyrinth seal and the HALO TM seal operating with pressure ratios as high as 8, temperatures to 300ºC, and tip surface speeds to 120 m/s c) Compare the labyrinth seal measured leakage with XLLaby® predictions at high temperature. The benchmarking is essential to trust, modify or discard current predictive models TRC funded project (2 years) TRC members benefit from existing high temperature test rig

11 (a) Learn operation of test rig and DAQ system (b) Install two seals (labyrinth and HALO) and perform leakage measurements with air for: (c) Revamp test rig for high speed operation Non-rotating and centered rotor Inlet temperature (30ºC-300ºC) Supply pressure (1 bar- 7 bar) Work to date for TRC funded project

12 TEST LABYRINTH SEAL

13 LEAKAGE: Labyrinth Seal Flow rate increases with supply pressure and decreases with inlet temperature due to changes in seal clearance and gas density. TESTS for low pressure ratios to 3.5 (> choking) 30C 300C

14 Modified Flow Factor Modified flow factor: Labyrinth Seal Flow factor allows comparison of different types of seals. For labyrinth seal, it removes effect of supply pressure and temperature. 30C 300C

15 Hydrostatic Advanced Low Leakage Seal All metal (no bristles) non-contacting seal TEST HALO TM Seal mm Direction of flow

16 TEST CONDITIONS (HALO TM SEAL)

17 Hydrostatic Advance Low Leakage (HALO) Seal PR: upstream pressure /ambient (exit) pressure HALO seal clearance closes with pressurization. Measurements at room temperature (30 °C) and no shaft rotation

18 LEAKAGE: HALO TM Seal Flow rate increases with supply pressure and decreases with air inlet temperature. TESTS conducted with much higher pressure ratios 30C 300C

19 Modified Flow Factor Modified flow factor: HALO TM Seal Modified flow factor much lower than for labyrinth seal 30C 300C

20 Leakage Comparison: Labyrinth & HALO) LABYRINTH HALO seal The HALOTM seal leaks 50% or less than the labyrinth seal. For pressure ratios (Ps/Pa) > 3.0, the HALOseal leaks ~¼ the flow rate of the labyrinth seal

21 Flow factor (Labyrinth & HALO) 300 C Labyrinth seals are an outdated technology. Industries seeking to increase efficiency by reducing (parasitic) secondary leakage losses will benefit greatly from a change in seal technology LABYRINTH HALO seal

22 REVAMP TEST RIG Issues Large vibrations of cantilevered rotor Critical speeds too low & air temperature too high Safety: containment at high speeds Drive motor speed limitations Solutions Balance rotor For high temperature, use a metal mesh foil bearing (MMFB) as a support. Use high speed router motor & construct containment guard. For operation at higher rotor speeds to reach a tip surface speed of 120 m/s (15 krpm)

23 REVAMP TEST RIG XLTRC 2 rotordynamic analysis Metal mesh bearing support adds stiffness and damping to original cantilevered rotor.

24 XLTRC 2 imbalance response predictions MMFB increases critical speed and determines a well damped system With MMFB Amplitude of motion at disc

25 TRC Budget Year II Support for graduate student (20 h/week) x $ 1,700 x 12 months$ 20,400 Fringe benefits (0.6%) and medical insurance ($191/month)$ 2,412 Travel to (US) technical conference$ 1,500 Tuition three semesters ($3,802 x 3)$ 10,138 Equipment and supplies for test rig$ 550 Year II$ 35,000 Year I $ 39,863 High Temperature Seals Research will quantify the leakage performance of a novel gas seal for high temperature gas turbines and steam turbines. RESEARCH PRODUCTS Reliable leakage database ASME journal publication Technical report (M.S. thesis)

26 Questions (?)

27 [1]San Andrés, L., and Ashton, Z., 2010, "Comparison of Leakage Performance in Three Types of Gas Annular Seals Operating at a High Temperature (300°C)," Tribol. Trans., 53(3), pp Learn more at References [2]Justak, J., and Doux, C., 2009, Self-Acting Clearance Control for Turbine Blade Outer Air Seals, ASME Paper GT


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