function 
 
 
   tgh = hotsim(var,twh,qrloss) 
 
 
   % evaluate heater average heat transfer performance 
 
 
   % Israel Urieli, 7/22/2002 
 
 
   % Modified 2/6/2010 to include regenerator qrloss 
 
 
   % Arguments: 
 
 
   %   var(22,37) array of variable values every 10 degrees (0 - 360) 
 
 
   %   twh - heater wall temperature [K] 
 
 
   %   qrloss - heat loss due to imperfect regenerator [J] 
 
 
   % Returned values: 
 
 
   %   tgh - heater average gas temperature [K] 
 
 
   % Row indices of the var, array: 
 
 
   TC = 1; 
 
 
   % Compression space temperature (K) 
 
 
   TE = 2; 
 
 
   % Expansion space temperature (K) 
 
 
   QK = 3; 
 
 
   % Heat transferred to the cooler (J) 
 
 
   QR = 4; 
 
 
   % Heat transferred to the regenerator (J) 
 
 
   QH = 5; 
 
 
   % Heat transferred to the heater (J) 
 
 
   WC = 6; 
 
 
   % Work done by the compression space (J) 
 
 
   WE = 7; 
 
 
   % Work done by the expansion space (J) 
 
 
   W  = 8; 
 
 
   % Total work done (WC + WE) (J) 
 
 
   P  = 9; 
 
 
   % Pressure (Pa) 
 
 
   VC = 10; 
 
 
   % Compression space volume (m^3) 
 
 
   VE = 11; 
 
 
   % Expansion space volume (m^3) 
 
 
   MC = 12; 
 
 
   % Mass of gas in the compression space (kg) 
 
 
   MK = 13; 
 
 
   % Mass of gas in the cooler (kg) 
 
 
   MR = 14; 
 
 
   % Mass of gas in the regenerator (kg) 
 
 
   MH = 15; 
 
 
   % Mass of gas in the heater (kg) 
 
 
   ME = 16; 
 
 
   % Mass of gas in the expansion space (kg) 
 
 
   TCK = 17; 
 
 
   % Conditional temperature compression space / cooler (K) 
 
 
   THE = 18; 
 
 
   % Conditional temeprature heater / expansion space (K) 
 
 
   GACK = 19; 
 
 
   % Conditional mass flow compression space / cooler (kg/rad) 
 
 
   GAKR = 20; 
 
 
   % Conditional mass flow cooler / regenerator (kg/rad) 
 
 
   GARH = 21; 
 
 
   % Conditional mass flow regenerator / heater (kg/rad) 
 
 
   GAHE = 22; 
 
 
   % Conditional mass flow heater / expansion space (kg/rad) 
 
 
   global 
 
 
   th 
 
 
   % heater temperature [K] 
 
 
   global 
 
 
   freq omega 
 
 
   % cycle frequency [herz], [rads/s] 
 
 
   global 
 
 
   ah 
 
 
   % heater internal free flow area [m^2] 
 
 
   global 
 
 
   awgh 
 
 
   % heater internal wetted area [m^2] 
 
 
   global 
 
 
   dh 
 
 
   % heater hydraulic diameter [m] 
 
 
   % Calculating the Reynolds number over the cycle 
 
 
   for 
 
 
   (i = 1:1:37) 
 
 
   gah(i) = (var(GARH,i) + var(GAHE,i))*omega/2; 
 
 
   gh = gah(i)/ah; 
 
 
   [mu,kgas,re(i)] = reynum(th,gh,dh); 
 
 
   end 
 
 
   % Average and maximum Reynolds number 
 
 
   sumre=0; 
 
 
   remax=re(1); 
 
 
   for 
 
 
   (i=1:1:36) 
 
 
   sumre=sumre + re(i); 
 
 
   if 
 
 
   (re(i) > remax) 
 
 
   remax = re(i); 
 
 
   end 
 
 
   end 
 
 
   reavg = sumre/36; 
 
 
   [ht,fr] = pipefr(dh,mu,reavg); 
 
 
   % Heat transfer coefficient 
 
 
   tgh = twh - (var(QH,37)+qrloss)*freq/(ht*awgh); 
 
 
   % Heater gas temperature [K] 
 
 
   fprintf( 
 
 
   '============ Heater Simple analysis =============\n' 
 
 
   ) 
 
 
   fprintf( 
 
 
   ' Average Reynolds number : %.1f\n' 
 
 
   ,reavg) 
 
 
   fprintf(' 
 
 
   Maximum Reynolds number : %.1f\n' 
 
 
   ,remax) 
 
 
   fprintf( 
 
 
   ' Heat transfer coefficient [W/m^2*K] : %.2f\n' 
 
 
   ,ht) 
 
 
   fprintf( 
 
 
   'heater wall/gas temperatures: Twh = %.1f[K], Tgh = %.1f[K]\n' 
 
 
   ,twh,tgh);