Relazione Hydraulic System

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Politecnico di Milano Dipartimento di Scienze e Tecnologie Aerospaziali Corso di Impianti e Sistemi Aerospaziali Laboratory n.2 Hydraulic system Mirko Ragni Number 843996 Academic year 2016-2017 2 Introduction In this relation, I am going to show all the calculation and reasoning that went in sizing the hydraulic system in the second laboratory of this course. Index • Symbols list…………………………………………………………………….3 • Problem description and resolution method……………………………………3 • Problem data……………………………………………………………………5 • Development of the calculations……………………………………………….6 • Results presentation…………………………………………………………….8 3 Symbols list • β = Coefficient of compressibility (Pascale) • F = Force (Newton) • k = Adiabatic dilation coefficient (dimensionless) • P = Pressure (Pascal) • Q = Volumetric flow rate ( 𝑚³ 𝑠 ) • t = time (seconds) • V = Volume (m³) • W = Power (Watt) • x = Travel of the piston (millimetres) Problem description and resolution method The problem asked to properly dimension two hydraulic jacks acting in series to ensure roughly the same travel and force on both jacks. In order to achieve this firstly I have calculated the maximum force that they have to overcome. Secondly, I have determined the diameter of the jack and the volume of the accumulator. Once I have determined these data I was able to calculate the power that the hydraulic pump has to deliver to the system. In the end, I have calculated the position errors of the two hydraulic jacks. 4 In the system shown in the figure, the pump feeds at constant pressure of 21 MPa the two jack connected in series to have equal displacements between them. The external loads consist of two equal forces equal to 25000 + 20x [N], where x is the stroke in millimeters, which has a maximum value of 600 mm and under normal…