function eta = effturbine_eps70(ns,ds,PR)
% File created by Violette Mounier (2017) - LAMD EPFL
% This function evaluates the performance of a radial inflow turbine, function of the following inputs:
% - ns [-] : specific speed
% - ds [-] : specific diameter
% - PR [-] : Pressure ratio [-]
% It is valid for a shroud to tip radius ratio  epsilon = 0.7
% For an isentropic efficiciency above 0.5 :
% 0.2 < ns < 1.2  
% 2.2 < ds < 8.2
% 1.5 < PR < 8.5

%% Inputs
x3=PR;
x2=ds;
x1=ns;

%% Model
eta= +9.182663.*x3+-2.278835.*x3.^2+0.2884514.*x3.^3+-0.02660791.*x3.^4+0.001649853.*x3.^5+9.119349.*x2+-2.507019.*x2.*x3+0.5493959.*x2.*x3.^2+...
-0.04216183.*x2.*x3.^3+0.00167889.*x2.*x3.^4+-3.167391e-07.*x2.*x3.^5+-2.032517.*x2.^2+0.1527024.*x2.^2.*x3+-0.04839117.*x2.^2.*x3.^2+0.002854551.*x2.^2.*x3.^3+...
-0.0001222634.*x2.^2.*x3.^4+0.2693897.*x2.^3+0.01194814.*x2.^3.*x3+0.001266321.*x2.^3.*x3.^2+6.329307e-10.*x2.^3.*x3.^3+-0.02164697.*x2.^4+-0.001429506.*x2.^4.*x3+...
-1.416799e-05.*x2.^4.*x3.^2+0.0009610422.*x2.^5+3.417001e-05.*x2.^5.*x3+133.6556.*x1+-44.82733.*x1.*x3+7.572129.*x1.*x3.^2+-0.4281241.*x1.*x3.^3+0.0113471.*x1.*x3.^4+...
1.767352e-05.*x1.*x3.^5+-76.39429.*x1.*x2+12.96657.*x1.*x2.*x3+-1.871027.*x1.*x2.*x3.^2+0.06608761.*x1.*x2.*x3.^3+-0.001717494.*x1.*x2.*x3.^4+18.10912.*x1.*x2.^2+...
-0.9731749.*x1.*x2.^2.*x3+0.1332014.*x1.*x2.^2.*x3.^2+-0.0004203146.*x1.*x2.^2.*x3.^3+-2.123584.*x1.*x2.^3+0.003832324.*x1.*x2.^3.*x3+-0.004589992.*x1.*x2.^3.*x3.^2+...
0.1165907.*x1.*x2.^4+0.001977552.*x1.*x2.^4.*x3+-0.002374422.*x1.*x2.^5+-360.1083.*x1.^2+88.27482.*x1.^2.*x3+-12.34935.*x1.^2.*x3.^2+0.4618588.*x1.^2.*x3.^3+...
-0.006431334.*x1.^2.*x3.^4+217.1688.*x1.^2.*x2+-23.08562.*x1.^2.*x2.*x3+2.422561.*x1.^2.*x2.*x3.^2+-0.03793256.*x1.^2.*x2.*x3.^3+-47.25572.*x1.^2.*x2.^2+1.465386.*x1.^2.*x2.^2.*x3+...
-0.1027536.*x1.^2.*x2.^2.*x3.^2+4.365014.*x1.^2.*x2.^3+-0.01503023.*x1.^2.*x2.^3.*x3+-0.1424971.*x1.^2.*x2.^4+367.447.*x1.^3+-65.13514.*x1.^3.*x3+7.636818.*x1.^3.*x3.^2+...
-0.1507052.*x1.^3.*x3.^3+-227.2949.*x1.^3.*x2+13.81684.*x1.^3.*x2.*x3+-0.9253103.*x1.^3.*x2.*x3.^2+40.11737.*x1.^3.*x2.^2+-0.5327752.*x1.^3.*x2.^2.*x3+-2.129502.*x1.^3.*x2.^3+...
-112.9759.*x1.^4+12.1091.*x1.^4.*x3+-1.362668.*x1.^4.*x3.^2+90.9158.*x1.^4.*x2+-1.729978.*x1.^4.*x2.*x3+-10.70946.*x1.^4.*x2.^2+-27.47435.*x1.^5+1.829747.*x1.^5.*x3+...
-8.60297.*x1.^5.*x2+-18.45993.*1+12.95407.*x1.^6+-1.797567e-05.*x2.^6+-5.222165e-05.*x3.^6;

end
