Lab 4 v2 impianto combustibile relazione

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1 Politecnico di Milano Dipartimento di Ingegneria Aerospaziale Corso di Impianti e Sistemi Aerospaziali FUEL SYSTEM Alessandro Daniele Galluzzi July 2016 2 1. Preface This relation has the purpose of choose between a series of pumps provided by a constructor for the feeding line of a double - engine aircraft. Figure 1 Figure 2 3 2. Index 1. Preface 2 2. Index 2 3. List of symbols 3 4. Description of the problem and method of resolution 4 5. Problem data 5 6. Results 5 3. List of symbols D Alimentation pipeline diameter [inch] A Alimentation pipeline section [ ] ̇ Minimum engine flow in m ass unit [ ] ̇ Maximum engine flow in mass unit [ ] Minimum engine flow [ ] Maximum engine flow [ ] . Minimum engine pressure [Pa] , Maximum engine pressure [Pa] , Minimum pump pressure [Pa] , Maximum pump pressure [Pa] L Pipeline length [m] λ Pipeline major head losses coefficient K Pipeline minor losses coefficient . Alimentation pipeline pressure losses [Pa] ρ Fuel density [ ] v Fluid speed [ ] 4 4. Description of the problem and resolution methods The fuel system is described in Figure 1 . The aircraft has two engines, two tanks and two pipelines of equal lenght and width. The system has also a cross - feed valve next to the pumps for safety reasons. For examples, in event of malfunction or failure of a feeding branch , one single pump must be able to supply enough fuel flow for both the engines. For this purpose a series of centrifugal pumps are proposed to fit the fuel system , which charactheristic curves of flow and pressure are described in the diagram of figure 2. Each engine has ( depending on his revolutions per minute ) well defined minimum and maximum values for pressure and flow rate, but due to the distance between tank and en- gine we have to calculate the pressure…