Effect of the order of accuracy in the accurate runge-kutta scheme for the determination of the transient true void fraction and pressure drops in pipes - Lopez Silva, Ricardo Alberto; Lecuona Neumann, Antonio; Nogueira Goriba, Jose Ignacio; Vereda Ortiz, Ciro Sebastian (VII Congreso ibérico y V congreso iberoamericano de ciencias y técnicas del frío, 2014)