SAWE UK Chapter Meeting

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1 SAWE UK Chapter Meeting Preliminary Aero Engine Weight Estimation Techniques for a Techno-economic and Environmental Risk Analysis Framework (TERA) Periklis Lolis p.lolis@cranfield.ac.uk

2 Contents Motivation Objectives Literature Survey Methodology Summary - Conclusions

3 Motivation Importance of preliminary weight estimation Aircraft Design Weight Estimation Engine Design Important information for the aircraft designer Important aspect for the accurate modeling of the engine that will help define the optimum design Cost Reduction SFC Reduction Emissions Reduction

4 Objectives Define and model the connection between engine parameters and engine weight Devise more accurate and practically applicable methods to calculate the engine weight Develop preliminary estimation methods for novel engine configurations (HBPR engines, Contra-rotating engines, etc) Study the influence of weight on engine, aircraft and mission parameters (Noise, Emissions, Cost, etc)

5 Literature Survey TERA Framework Preliminary Weight Estimation Methods Single equation methods Clavier method Gerend and Roundhill method Sagerser method NASA WATE method

6 The TERA Framework A TERA Framework performs Techno-economic and Environmental Risk Analysis Helps define the most suitable engine for a given application Consists of modules that model various parameters Characteristics Capabilities Multi-disciplinary optimization Parametric analysis Trade-off studies Tool developed by CU is used and may be used within a series of EU projects (VITAL, NEWAC, DREAM, etc)

7 Aero TERA Modules Engine Performance (TURBOMATCH, PROOSIS, EVA) Weight, Dimensions and Cost (WeiCo) Aircraft Perfomance (HERMES) Emissions (HEPHAESTUS) Noise (SOPRANO) Engine Life and Cost (HESTIA) Initial concept by: Kyprianidis, K. et al. 2010

8 Preliminary Weight Estimation Methods Whole engine based approach Single equation methods Clavier method Gerend and Roundhill method Component based approach Sagerser method NASA WATE method

9 Single Equation Methods (1/3) Method Weight Correlations Whitehead and Brown (1953) WT = f (W des ) Pennington (1959) Torenbeek (1975) Raymer (1989) WT = f (FN) WT = f (FN to, W to, BPR, CPR) WT = f (FN to, BPR) Svoboda (2000) WT = f (Fn to )

10 Single Equation Methods (2/3) Advantages Fast methods Require few inputs Inputs are readily available Disadvantages Not capturing all weight related parameters Low accuracy (error greater than 10%)

11 Single Equation Methods (3/3) Svoboda and Torenbeek methods have error less than 30% Raymer method has error up to 240% Svoboda and Torenbeek methods have a great scatter Raymer method for small size engines has a good result concetration

12 Clavier Method Weight estimated by using a parameter Parameter = OPR 2 x BPR x W + Direct method + Few Inputs - Poor database quality - Parameter lacks important variables - Large Parameter values result in negative weight Clavier 2008, Msc Thesis

13 Gerend and Rounhill Method Uses correction factors for various variables (PR, BPR, Life, EIS, TET, W, etc) taken from diagrams. Comparative method# + Fast method + Acceptable trade-off between simplicity and accuracy (error ~10%) + Takes into account many variables - Old method (1970) - Diagrams don t cover recent values of the variables - Not all the parameters studied have a correction factor Used in CU by Whellens (2003) and Colmenares Quintero (2009)

14 Sagerser Method Component based method Developed for VTOL/STOL engines but applies to cruise engines as well Uses correction factors from component data to adjust the equations Comparative method# + Good accuracy (error less than 10%) + Estimates the weight of each component + Takes into account many aspects of the engine - Old method (1971) - Requires many input values

15 NASA WATE Method Component based method Estimates the weight by performing simple preliminary design + Very good accuracy (error 5% - 10%) + Estimates the weight of each component + Numerous improvements and extensions available - Old method (1977) - Requires many input values - Uses correction factors based on an old database - Requires long calculation time

16 Methodology New method targets High accuracy Reduced amount of input variables Flexible method Include new components (contra-rotating engines, intercoolers, recuperators) Possible solutions Whole engine based approach Component based approach Combined approach

17 Whole engine approach Database Refinement and Validation Aims Study the connection of weight with engine parameters Produce a fast and reliable weight estimation method Advantages + Fast method + Acceptable accuracy (error less than 10%) Weight Diagrams Weight Prediction Analysis Disadvantages - Based on existing engines - Not flexible

18 Component approach Aims Produce an accurate method for preliminary weight estimation Minimize the inputs - assumptions No correction factors Design Assumptions Component Design Weight Calculation Cycle Inputs Advantages + High levels of accuracy (error less than 5%) + Flexible method + Captures future designs Disadvantages - Slower method - Many inputs - Difficult to validate

19 Combined approach Aims Improve the results of the component based approach with elements of the whole engine approach Correction Factors Assumptions Component Design Weight Calculation Cycle Inputs Advantages + Flexible method + Accurate method (error less than 5%) Disadvantages - Difficult to validate - Uses correction factors

20 Integration into TERA Aims Development of a weight module that will be integrated into the TERA Framework Include components and configurations that are studied within the TERA Framework - Intercoolers - Recuperators - Open rotor engines - High bypass engines - Geared turbofans Sensitivity analysis

21 Summary - Conclusions The TERA Framework is a versatile tool for selecting the most suitable engine for a given application Existing preliminary weight estimation methods are either too simple and lack accuracy or reasonably accurate with a penalty in simplicity Three new methods will be developed for the preliminary weight estimation (whole engine based approach, component based approach, combined method) Best method will be integrated into the TERA Framework and new components and configurations will be studied

22 SAWE UK Chapter Meeting Thank you for your attention Contact details: Periklis Lolis