Određivanje sile kočenja na aerodinamičkim kočnicama pomoću numeričkih simulacija

Abstract

Ovaj rad predstavlja rezultate istraživanja uticaja aerodinamičkih kočnica, postavljenih na krov brzog voza, na strujno polje i ukupnu silu kočenja. Voz se sastoji od dve lokomotive, na svakom kraju, i četiri putnička vagona., ukupne dužine 121m. Aerodinamičke kočnice stvaraju silu kočenja povećavanjem aerodinamičkog otpora pomoću izvučenih panela na krovu voza. Simulacije strujanja su urađene softverom Fluent 12.1, za voz bez, sa jednom, dve i tri aerodinamičke kočnice, pri brzinama od 30, 50 i 70m/s. Sila otpora po jedinici površine panela je određena kao funkcija brzine voza i položaja aerodinamičke kočnice. Doprinosi ukupnoj sili kočenja svake od kočnica, određeni simulacijama su: za prvu 24%, za drugu 15% i za treću 14.8% i pokazali su , zajedno sa raspodelama pritisaka po panelima, dobro slaganje sa proračunima aerodinamičkog otpora za ravnu ploču upravno postavljenu prema strujanju.

This work presents the research results of the aerodynamic brake influence, mounted on the high-speed train's roof, on the flow field and overall braking force. The train consists of two locomotives at each end and four passenger cars between, with 121m of overall length. Aerodynamic brakes are designed to generate braking force by means of increasing the aerodynamic drag by opened panels over the train. Flow simulations were made by Fluent 12.1 software, for the train without and with one, two and three aerodynamic brakes, and velocities of 30, 50 and 70m/s. Drag force per unit panel area was determined as a function of train's velocity and the brake position. Contributions to train's gross braking force of each brake, obtained by simulations were: for first 24%, for second 15% and third 14.8%, and showed, also with panels' pressure distribution, good correlation with the aerodynamic drag calculations for flat plate orthogonally disposed to flow stream.