R/ff.R

In ratral/hyd4gpv: General Purpose Valve functions

#' @title Ff Liquid critical pressure ratio factor
#' @description Ff is the liquid critical pressure ratio factor. This factor is
#' the ratio of the apparent vena contracta pressure at choked flow conditions
#' to the vapor pressure of the liquid at inlet temperature (ISA-75.01.01-2007).
#' At vapor pressures near zero, this factor is 0.96.
#' @author Dr. Raúl Trujillo Álvarez \email{dr.ing.trujillo@gmail.com}
#' @param temp is in °C
#' @return Liquid critical pressure ratio factor Dimensionless
#' @export
#' @examples
#' ff(15)
ff <- function(temp = 15){
  pv <- vapour_pressure(temp)
  #  the critical thermodynamic pressure for water is 221.2 bar
  pc <- 221.2
  return(0.96-0.28*sqrt(pv/pc))
}