function 
 
 
   [mu,kgas,re] = reynum(t,g,d) 
 
 
   % evaluate dynamic viscosity, thermal conductivity, Reynolds number 
 
 
   % Israel Urieli, 7/22/2002 (mu units correction 2/13/2011) 
 
 
   % Arguments: 
 
 
   %   t - gas temperature [K] 
 
 
   %   g - mass flux [kg/m^2.s] 
 
 
   %   d - hydraulic diameter [m] 
 
 
   % Returned values: 
 
 
   %   mu - gas dynamic viscosity [kg/m.s] 
 
 
   %   kgas - gas thermal conductivity [W/m.K] 
 
 
   %   re - Reynolds number 
 
 
   global 
 
 
   cp 
 
 
   % specific heat capacity at constant pressure [J/kg.K] 
 
 
   global 
 
 
   mu0 
 
 
   % dynamic viscosity at reference temp t0 [kg.m/s] 
 
 
   global 
 
 
   t0 t_suth 
 
 
   % reference temperature [K], Sutherland constant [K] 
 
 
   global 
 
 
   prandtl 
 
 
   % Prandtl number 
 
 
   mu = mu0*(t0 + t_suth)/(t + t_suth)*(t/t0)^1.5; 
 
 
   kgas = cp*mu/prandtl; 
 
 
   re = abs(g)*d/mu; 
 
 
   if 
 
 
   (re < 1) 
 
 
   re = 1; 
 
 
   end 
 
 

   function 
 
 
   [ht,fr]=pipefr(d,mu,re); 
 
 
   % evaluate heat transfer coefficient, Reynolds friction factor 
 
 
   % Israel Urieli, 7/22/2002 (corrected header 2/20/2011) 
 
 
   % Arguments: 
 
 
   %   d - hydraulic diameter [m] 
 
 
   %   mu - gas dynamic viscosity [kg.m/s] 
 
 
   %   re - Reynolds number 
 
 
   % Returned values: 
 
 
   %   ht - heat transfer coefficient [W/m^2.K] 
 
 
   %   fr - Reynolds friction factor ( = re*fanning friction factor) 
 
 
   global 
 
 
   cp 
 
 
   % specific heat capacity at constant pressure [J/kg.K] 
 
 
   global 
 
 
   prandtl 
 
 
   % Prandtl number 
 
 
   % Personal communication with Allan Organ, because of oscillating 
 
 
   % flow, we assume that flow is always turbulent. Use the Blasius 
 
 
   % relation for all Reynolds numbers: 
 
 
   fr=0.0791*re^0.75; 
 
 
   % From Reynolds simple analogy: 
 
 
   ht=fr*mu*cp/(2*d*prandtl); 
 
 

   function 
 
 
   [st,ht,fr] = foilfr(d,mu,re) 
 
 
   % evaluate regenerator wrapped foil stanton number, friction factor 
 
 
   % Israel Urieli, 7/22/2002 
 
 
   % Arguments: 
 
 
   %   d - hydraulic diameter [m] 
 
 
   %   mu - gas dynamic viscosity [kg.m/s] 
 
 
   %   re - Reynolds number 
 
 
   % Returned values: 
 
 
   %   st - Stanton number 
 
 
   %   ht - heat transfer coefficient [W/m^2.K] 
 
 
   %   fr - Reynolds friction factor ( = re*fanning friction factor) 
 
 
   global 
 
 
   cp % specific heat capacity at constant pressure [J/kg.K] 
 
 
   global 
 
 
   prandtl % Prandtl number 
 
 
   if 
 
 
   (re < 2000) % normally laminar flow 
 
 
   fr = 24; 
 
 
   else 
 
 
   fr = 0.0791*re^0.75; 
 
 
   end 
 
 
   % From Reynolds simple analogy: 
 
 
   st=fr/(2*re*prandtl); 
 
 
   ht=st*re*cp*mu/d; 
 
 

   function 
 
 
   [st,fr] = matrixfr(re) 
 
 
   % evaluate regenerator mesh matrix stanton number, friction factor 
 
 
   % Israel Urieli, 7/22/2002 
 
 
   % Arguments: 
 
 
   %   re - Reynolds number 
 
 
   % Returned values: 
 
 
   %   st - Stanton number 
 
 
   %   fr - Reynolds friction factor ( = re*fanning friction factor) 
 
 
   global 
 
 
   prandtl 
 
 
   % Prandtl number 
 
 
   % equations taken from Kays & London (1955 edition) 
 
 
   st = 0.46*re^(-0.4)/prandtl; 
 
 
   fr = 54 + 1.43*re^0.78;