R/bend_eff.R

In markhogue/AeroSampleR: Estimate Aerosol Particle Collection Through Sample Lines

#' bend efficiency
#'
#' In order to run this function, first produce a particle distribution
#' with the `particle_dist` function, then produce a parameter set with
#' the `set_params` function. Both of these results must be stored as
#' per examples described in the help set with each.
#'
#' @param df is the particle data set (data frame) established with the
#' `particle_dist` function
#' @param params is the parameter data set for parameters that are not
#' particle size-dependent
#' @param bend_angle bend angle in degrees
#' @param bend_radius bend radius in m
#' @param method choice of models: Pui, McFarland, or Zhang
#' @param elnum element number to provide unique column names
#'
#' @references
#' A. R. McFarland, H. Gong, A. Muyshondt, W. B. Wente, and N. K. Anand
#' Environmental Science & Technology 1997 31 (12), 3371-3377
#' <doi:10.1021/es960975c>
#'
#' Pusheng Zhang, Randy M. Roberts, André Bénard,
#' Computational guidelines and an empirical model for particle deposition
#' in curved pipes using an Eulerian-Lagrangian approach,
#' Journal of Aerosol Science, Volume 53, 2012, Pages 1-20,ISSN 0021-8502,
#' <doi:10.1016/j.jaerosci.2012.05.007>
#'
#' David Y. H. Pui, Francisco Romay-Novas & Benjamin Y. H. Liu (1987)
#' Experimental Study of Particle Deposition in Bends of Circular Cross
#' Section, Aerosol Science and Technology, 7:3, 301-315,
#' <doi:10.1080/02786828708959166>
#'
#' @returns data frame containing original particle distribution with added
#' data for this element
#'
#' @examples
#' df <- particle_dist() # set up particle distribution
#' params <- set_params_1("D_tube" = 2.54, "Q_lpm" = 100,
#' "T_C" = 25, "P_kPa" = 101.325) #example system parameters
#' df <- set_params_2(df, params) #particle size-dependent parameters
#' df <- probe_eff(df, params, orient = 'h') #probe orientation - horizontal
#' df <- bend_eff(df, params, method='Zhang', bend_angle=90,
#' bend_radius=0.1, elnum=3)
#' head(df)
#' @export
#'
bend_eff <- function(df, params, method, bend_angle, bend_radius, elnum) {
    # cat('This function appends a new eff_bend.. column to the data
    # frame') cat('\n')

    angle_rad <- bend_angle * pi/180
    rat_curv <- bend_radius/(params$D_tube/2)

    if (method == "Pui") {
        ifelse(params$Re < 6000, eff_bend <- (1 + (df$Stk/0.171)^(0.452 *
            df$Stk/0.171 + 2.242))^-(2 * angle_rad/pi), eff_bend <- exp(-2.823 *
            df$Stk * angle_rad))
    }
    if (method == "Zhang") {
        eff_bend <- exp(-0.528 * angle_rad * df$Stk^((2)^(1/rat_curv)) *
            rat_curv^0.5)
    }
    if (method == "McFarland") {

        a <- -0.9526 - 0.05686 * rat_curv
        b <- (-0.297 - 0.0174 * rat_curv)/(1 - 0.07 * rat_curv + 0.0171 *
            rat_curv^2)
        c <- -0.306 + 1.895/rat_curv^0.5 - 2/rat_curv
        d <- (0.131 - 0.0132 * rat_curv + 0.000383 * rat_curv^2)/(1 - 0.129 *
            rat_curv + 0.0136 * rat_curv^2)

        eff_bend <- 0.01 * exp((4.61 + a * angle_rad * df$Stk)/(1 + b *
            angle_rad * df$Stk + c * angle_rad * df$Stk^2 + d * angle_rad^2 *
            df$Stk))
        # this is necessary to remove very high results when
        # denominator of the function above approaches zero
        if (df$Stk < 2.065 && df$Stk > 2.05)
            eff_bend <- 0
        # More removal of out-of-range results
        if (eff_bend >= 1 && df$Stk > 1)
            eff_bend <- 0
    }

    eff_bend[eff_bend > 1] <- 1
    df <- cbind(df, eff_bend)
    names(df)[length(df)] <- paste0("eff_bend_", as.character(elnum))
    df
}