Computer simulation flat plates

For computer simulation of the performance of flat-plate solar collectors, several methods and computer programs have been used. Finite-difference [57], network [26,37,54,57], stochastic [58], dynamic [59], and simplified models [60] and methods (see Ref. [99]) have been elaborated. 

In catalytic channels, the flat plate surface temperature in Eq. (3.32) is attained at the channel entry (x O). As the catalytic channel is not amenable to analytical solutions, simulations are provided next for the channel geometry shown in Fig. 3.3. A planar channel is considered in Fig. 3.3, with a length L = 75 mm, height 21) = 1.2 mm, and a wall thickness 5s = 50 pm. A 2D steady model for the gas and solid (described in Section 3.3) is used. The sohd thermal conductivity is k = 6W/m/K referring to FeCr alloy, a common material for catalytic honeycomb reactors in power generation (Carroni et al., 2003). Surface radiation heat transfer was accounted for, with an emissivity = 0.6 for each discretized catalytic surface element, while the inlet and outlet sections were treated as black bodies ( = 1.0). To illustrate differences between the surface temperatures of fuel-lean and fuel-rich hydrogen/air catalytic combustion, computed axial temperature profiles at the gas—wall interface y=h in Fig. 3.3) are shown in Fig. 3.4 for a lean (cp = 0.3) and a rich cp = 6.9) equivalence ratio, p = 1 bar, inlet temperature, and velocity Tj = 300 K and Uin = 10 m/s, respectively. The two selected equivalence ratios have the same adiabatic equilibrium temperature, T d=1189 K. 

Flat Plate Boundary Layer. A subsonic flat-plate boundary-layer flow is investigated to validate the STG method for the zonal RANS-LES configuration comparing the results with a pure RANS, pure LES, and available experimental data. The freestream Mach numbers are M = 0.4 and M = 2.3 and the freestream Rejmolds numbers based on the momentum thickness at x/Sq = 0 are Reo = 1400 and Re = 4200, respectively, where denotes the boundary-layer thickness at the inlet of computational domain of the pure LES, pure RANS, and the embedded LES part of the zonal RANS-LES simulation. The inflow boundaries of the pure LES, pure RANS, and the embedded LES part of the zonal RANS-LES simulation are located at x/5o = 0. 

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