ME3531 Aircraft Systems Chapter 1.1 Introduction of Hydraulic Power PDF

ME3531 Aircraft Systems Chapter 1.1: Introduction of Hydraulic Power For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Objective How is hydraulic power created on an aircraft...

ME3531 Aircraft Systems Chapter 1.1: Introduction of Hydraulic Power For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Objective How is hydraulic power created on an aircraft Brief describe the basic hydraulic power system and the function of each individual component. Overview of various aircraft sub system which is powered by hydraulic power. Why hydraulic power State the relationship between pressure, force and area Solve simple problems using Pascal’s law Fundamental laws of hydraulic Page  2 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power How is hydraulic power created on an aircraft? Turbofan Engine Accessory Gear Box Page  3 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Aircraft Fuel Tank Fuel Pump Fuel & Hydraulic Oil Reservoir Return Filter Heat Exchanger Case Drain Filter Aircraft Combustion Chamber Relief valve Engine Driven Pressure Filter Selector Valve Actuator Hydraulic Pump Page  4 For Training Purpose Only Hydraulic Power Page  9 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Why Hydraulic Powered System Light weight Less fuel is burned. Minimum maintenance requirement Lower aircraft downtime which translates to more profit from longer flying hours. Page  6 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Why Hydraulic Powered System Simplification of inspection Ease of inspection of components hence inspection time is reduced resulting in saving of manpower. Hydraulic leak on the wing top Ease of installation Components are installed into aircraft with ease. Page  7 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Pascal's law Pascal's law is a principle in fluid mechanics that states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. Hydraulic oil molecules Bottle filled with hydraulic fluid Page  8 For Training Purpose Only Hydraulic Power Application of Pascal's law Application of a small input force on a smaller area (B) as compare to area (A) will lift a heavier load (W). The distance travelled by the area B will be longer as compared to area A. Useful Formula: Pressure (𝑚𝑁2 ) = 𝐹𝑜𝑟𝑐𝑒 (𝐹) = 𝑊𝑒𝑖𝑔ℎ𝑡(𝑊) ------- (1) 𝐴𝑟𝑒𝑎 (𝐵) 𝐴𝑟𝑒𝑎 (𝐴) 3 Volumetric Flow Rate (Q) (𝑚 ) = Area of cross section (A) multiple by 𝑠 Average Velocity (V) --------- (2) Page  13 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Example of Calculations With the given data, Find the Output Force (F) and Mechanical Advantage (MA) Area of Smaller Piston (a) = 2 𝑚2 Area of Larger Piston (A) = 10 𝑚2 Input force (f) = 100 N Input Output 𝐹 Output Force = = 100 = 500 N 10 2 Mechanical Advantage = 𝐹 = 𝐴 = 500 = 10 = 5 𝑓 𝑎 100 2 Page  10 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Fundamental laws of hydraulics Hydraulic pumps create flow and NOT PRESSURE Gear Pump Suction Displacing liquid Discharge Page  11 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Passage Fundamental laws of hydraulics returning to Bore side reservoir is closed Resistance to flow create pressure 1 Gear Pump Linear Actuator Passage returning to reservoir is opened 1. Which actuator move (Extend)? 2 2. Which actuator has a higher resistance to flow at Linear Actuator the bore side? Page  12 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Fundamental laws of hydraulics Passage returning to reservoir is Flow determines actuator speed Bore side partially Gear Pump 1 open 1 Linear Actuator Gear Pump 2 Passage returning to reservoir is fully opened 2 1. Which actuator will extend faster? Linear Actuator Note: Both gears are operating at the same speed (RPM) Page  13 For Training Purpose Only Hydraulic Power Fundamental laws of hydraulics Passage returning to reservoir is Pressure determines actuator force Bore side fully open Gear Pump 1 Load 1 Linear Actuator Gear Pump 2 Passage returning to reservoir is fully opened Load 2 1. Which actuator will have higher actuator force? Note Linear Actuator Gear pump 1 has a higher flow rate than gear pump 2 second. Page  18 Both load have similar weight For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Fundamental laws of hydraulics Passage Fluid under pressure takes the path of least resistance returning to Bore side reservoir is fully closed 1 Gear Pump 1 Linear Actuator Passage returning to reservoir is fully opened 2 1. Which actuator will the pump fluid flow towards? Linear Actuator Page  15 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Fundamental laws of hydraulics When a fluid (liquid) moves from an area of high pressure to an area of low pressure (pressure drop) without performing useful work, heat is generated A B P T M Typical Hydraulic system set up with open center selector valve Page  16 For Training Purpose Only  Official (Closed), Non-Sensitive Hydraulic Power Recap How is hydraulic power created on an aircraft Brief describe the basic hydraulic power system and the function of each individual component. Overview of various aircraft sub system which is powered by hydraulic power. Why hydraulic power State the relationship between pressure, force and area Solve simple problems using Pascal’s law Fundamental laws of hydraulic Page  17 For Training Purpose Only