2.4.2: Highly Loaded Compressor Blades

Transcription

1 2003 NASA/DoD UAPT PROGRAM ANNUAL REVIEW URETI on Aeropropulsion and Power Technology Sponsored by NASA and DoD 2.4.2: Highly Loaded Compressor Dr. Lakshmi Sankar (UAPT PI) Mr. Vishwas Iyengar(GRA) School of Aerospace Engineering 2003 Annual Review At Georgia Tech September 24-25, 2003

2 Overview Research Objectives Approach Results during the Reporting Period Collaboration Publications Concluding Remarks

3 Research Objectives Explore active and passive means of achieving very high pressure ratios in compressors. Passive Techniques include: Design of Compressor using a Multi-Disciplinary Approach, taking into account the uncertainties in the operating conditions as well as numerical models. This is being done in collaboration with Task 2.1. Recirculation Control End Wall Treatment Active Control Techniques include: Actively controlled bleeding Synthetic and/or pulsed jets Trailing Edge Blowing

4 Approach A spatially high order 3-D unsteady compressible flow solver is being used. An implicit time marching scheme is being used, to ensure time-accurate solutions may be obtained. The algorithm has been parallelized for shared memory machines (e.g., SGI Origin) as well as distributed processors/clusters. This solver has been extensively validated for helicopter rotors, wind turbines, propfans, and fixed wing configurations. Our goal is to understand and evaluate the physical phenomena of interest, rather than development of yet another CFD code.

5 Results Obtained During the Past Year Validated NASA Rotor 37 and NASA Rotor 67 configuration. This was done in collaboration with Task 2.1. Identified regions where stall and surge are likely for the Rotor 67 configuration. Implemented Recirculation control model. Obtained preliminary results for recirculation control of Rotor 67.

6 Grid: 60x36x21 5 points in the clearance gap Tip Clearance Gap was modeled with periodic boundary condition. Rotor 37 Configuration

7 Rotor 37 Performance Map (Design RPM) Total Pressure Ratio Measured characteristic performance map at Design Speed (Rotor 37) Mass Flow Rate (kg/sec) Experimental Rotor 37 (Design Speed) Computed Design Speed = RPM Experimental results obtained from Bright et. al.- NASA Glenn.

8 Rotor 37 Performance Map (70% Design RPM) Computed and Measured characterstic performance map at 70% design speed (Rotor 37) 1.6 Total Pressure Ratio Mass Flow Rate (kg/sec) Computed Experimental

9 Rotor 67 Configuration Rotor 67 grid has 125 cells in the streamwise direction, 63 and 41 cells in the radial and circumferential directions, respectively. The clearance gap was spanned by six cells in the radial direction. Design rotational speed = RPM, tip leading edge speed is 429 m/sec Tip relative Mach number 1.38.

10 Rotor 67 Performance at Off-Design Conditions Performance Map for a NASA Rotor Unstable Operating Points Total Pressure Ratio CFD Results Mass-flow Rate (kg/sec)

11 Variation of Mass Flow Rate vs. Pressure Ratio for Rotor 67 under High Mass Flow Rate Conditions Massflow Rate Vs Pressure Fluctuation % Total Pressure Ratio 25 mdot=30.25 kg/sec % Massflow Rate Massflow Rate vs Pressure Fluctuation % Total Pressure Ratio 25 mdot=32 kg/sec % Massflow Rate

12 Rotor 67 Behavior under Off-Design Conditions Massflow Rate Vs Pressure Fluctuation % Total Pressure Ratio Increasing variations in mass flow rate and pressure ratio % Ma ssflow Ra te mdot=29.5 kg/sec

13 Recirculation Control Concept Recirculation Treatment Concept: Recently studied by Hathaway (2002). Injection Bleed m 2 m 1 Case In Flow Rotor Hub

14 Recirculation Control Approach (contd.) The model requires both the injected and the bleed mass flow rates to be the same. The injected fluid is directed to lie along the casing endwall to energize the low momentum fluid. The injection port is located just upstream of the region of low momentum fluid.

15 Recirculation (contd.) 4-5 % of prescribed mass flow rate is bled. The bleed valve removed some air from the compressor, as specified by. m b = K b A b p K b is the bleed valve constant and is related to the valve geometry A b is the bleed port cross sectional area p is the pressure drop across the bleed valve.

16 Stable Operation Using Recirculation Recirculation was found to achieve stable operation of the compressor at off-design conditions Massflow Rate Vs Pressure Fluctuations (With Control) Control Controlled No Control % Total Pressure ratio Uncontrolled % Massflow Rate

17 Collaboration We requested and received a grid generator (TCGRID) from Dr. Rod Chima of NASA Glenn Research Center. We have briefed: Alex Stein of GE Power Systems Dennis Huff and Rakesh Srivastava of NASA Glenn Dr. Hall and Dr. Gupta of GE Corporate Research Center Peter Lorber and Alan Egolf of United Technologies Research Center/Sikorsky.

18 Publications A paper on our recirculation control work has been accepted for publication at the AIAA Aerospace Sciences Meeting in Reno, NV, January A Master s degree special problem report on validation studies is being prepared in collaboration with Task 2.1.

19 Future Plans Task Schedule: Task Identification of Concepts, configurations Systematic Evaluation of Concepts Applications to multi-stage rotors Final Report Yr 1Yr 2Yr 3Yr 4 Yr 5