The heater heat transfer performance function 'hotsim'
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); |
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Stirling Cycle Machine Analysis by Israel
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