Page 1 Class Example / Notes Primary Cycle Parameters Optimized to Minimize Fuel Consumption and Maximize Power –Overall Pressure Ratio (OPR or P3QP2) –Cycle Temperature (RIT or T4) Engine “Sized” to Meet Power Demands (Design Point) –Inlet Flow (Wc) Set to Match Power Requirement Note – Sizing is Direct Driver on Weight Generally Speaking Increasing T4 Reduces Engine Size for a Given Power Requirement Increasing OPR Reduces Fuel Consumption –To a Point, then the Trend Reverses –Component Efficiencies Strongly Influence These Trades Same Holds for Cooling Air, Parasitic Losses, etc. Single Spool Turboshaft – Overview

Page 2 Class Example / Notes Construct and Execute a Cycle for the Following T4 = 2000° R, OPR = 12, 100#/s Wc –Baseline Component Efficiencies =85% (HPC and HPT) –Burner Pr Loss = 5%, Nozzle PR = 1.05 What Flow is Required to Produce SHP What is the Impact of Changing T4 +500° What About Increasing Component Efficiency 5% Single Spool Turboshaft – Example 1 OPRBurner Pr Loss T4Nozzle PR Wc

Page 3 Class Example / Notes Reset the Base Cycle Conditions T4 = 2000° R, OPR = #/s Wc –Baseline Component Efficiencies =85% –Burner Pr Loss = 5%, Nozzle PR = 1.05 Add Automatic Iteration to Vary Flow to Hold Power Constant Sweep T4 from 2000° to 3000° in Increments of 250° Sweep OPR from 12 to 20 in Increments of 2 Redo with 90% Component Efficiencies Single Spool Turboshaft – Example 2 OPRBurner Pr Loss T4Nozzle PR Wc

Page 4 Class Example / Notes Lets Examine the Impact to Fuel Consumption and Sizing Single Spool Turboshaft – Example 2 Results 2000° T4 3000° T4 2500° T4 12 OPR 20 OPR 12 OPR 2500° T4 85% Component Eff 90% Component Eff

Page 5 Class Example / Notes Design Mode Engine Components Sized to Meet Continuity and Power Balance –Continuity  Exit Corrected Flow of Component = Inlet Corrected Flow of Next Component Area Sized to Ensure Continuity –Power Balance  Work of Turbine = Work of Compressor + Loads Expansion Ratio of Turbine Set to Meet Power Demands Off-Design Mode Areas are Fixed Continuity Sets the Match of the Compressor Turbine Expansion Ratio and Speed Vary to meet Power Demand Single Spool Turboshaft – Off Design Matching

Page 6 Class Example / Notes Design Point Operation (Areas Sized for Contiuity) Iteration VariableTarget Variable (Independent)(Dependent) Vary Wc Inletto getSHP Load (user input / user defined balance) Vary Loadto getZero Net Torque (power balance / automatic) Vary P/P HPTto getNozzle P/P (desired value / automatic) Vary Wfuelto getT4 (user input / power management) Single Spool Turboshaft – Solution Matrix Definition Off-Design Operation (Areas Known) Iteration VariableTarget Variable (Independent)(Dependent) Vary Wc Inletto getContinuity HPC (map / automatic) Vary Op-Line HPCto getContinuity HPT (map / automatic) Vary P/P HPTto getContinuity Nozzle (compressible flow / automatic) Vary Wfuelto getT4 (user input / power management) Vary Nshaftto getNshaft (user input / automatic)

Page 7 Class Example / Notes Reset the Base Design Point T4 = 2000° R, OPR = #/s Wc –Baseline Component Efficiencies =85% –Burner Pr Loss = 5%, Nozzle PR = 1.05 Confirm Off-Design Matches Design Point Lets Examine the Phenomena of Engine “Matching” Close the HPT Area 10% (use scale_hpt_area) –What Happens to Compressor Flow and PR –Why? Now Open the HPT Area 10% –What Happens to Compressor Flow and PR Single Spool Turboshaft – Example 3 Wc PR Nc Base Close HPT Area Open HPT Area