Submodel

Embedded in such models, in which variations were developed [12] are further detailed. The laminar burning velocity is expressed as a function of fuel type, fuel/ air ratio, level of exhaust gas recirculation, pressure, temperature, etc. Furthermore, submodels have been developed to describe the impact of engine speed, port-flow control systems, in-cylinder gross-flow motion (i.e., swirl, tumble, squish), and turbulent fluctuations u. Thus, with a wider knowledge base of the parametric impact of external variables, successful modeling of... 

STATISTICAL MECHANICS AS THE SECOND SUBMODEL. The interaction potential obtained via quantum mechanics constitutes the input necessary to obtain a statistical description of many water molecules interacting at a given pressure and temperature. 

Fully integrated submodel capability simplifies the simulation of complex systems. 

While most authors have used the finite-difference method, the finite element method has also been used—e.g., a two-dimensional finite element model incorporating shrinkable subdomains was used to de.scribe interroot competition to simulate the uptake of N from the rhizosphere (36). It included a nitrification submodel and found good agreement between ob.served and predicted uptake by onion on a range of soil types. However, while a different method of solution was used, the assumptions and the equations solved were still based on the Barber-Cushman model. 

Output from the soil erosion, pesticide fate, and economics submodels may not be needed for ET landfill cover evaluation and design they can be disregarded without affecting other components of the model estimate. 

UNSAT-H does not address the effects of soil density on plant growth and water balance. Disadvantages caused by the computational methods used to estimate soil water flow include the following (1) the model requires the user to choose from several submodels to solve the Richards equation this choice should be made by a person with training in advanced soil physics and (2) the model requires the input of several soil parameters that are difficult to estimate for the completed cover soil. 

UTM-TOX. The Unified Transport Model for Toxicants (UTM-TOX, 52) was developed at Oak Ridge National Laboratory (ORNL) on the base of the ORNL Unified Transport Model (UTM), itself under development from the early 1970 s. UTM-TOX includes air, water, and terrestrial submodels. The aquatic fate submodel includes volatilization, hydrolysis, biolysis, photolysis, and sorption equilibria. Sorbed phases are assumed unreactive in the 1982 version. 

AT123D (31) is a series of soil or groundwater analytical submodels, each submodel addressing pollutant transport in 1-, 2-, or 3-dimensions for saturated or unsaturated soils for chemical, radioactive waste heat pollutants and for different types of releases. The model can provide up to 450 submodel combinations in order to accommodate various conditions analytically. 

The previous model setup included an identical horizontal resolution for ocean and atmosphere, and online coupling was implemented in the ECHAM submodel with an exchange rate of 3 hours. In the current model setup atmosphere and ocean are coupled online using the Ocean-Atmosphere-Sea Ice-Soil (OASIS) coupler [Valcke et al (2004)] with a coupling time step of one day. OASIS passes boundary condi-... 

Figure 15. Comparison of curves Jm (a) and /u (b) versus t predicted by different submodels for a system with linear adsorption. Continuous line rigorous solution of transientwithboundaryconditioncM(/o + 0 = V7 dashedline rigorous(transient)...

Figure 16. Jm versus t predicted by the same submodels as in Figure 15, but with...

Figure 17. Comparison of Ju versus t plots predicted by different submodels for a system with one type of site (adsorbing and internalising) linear isotherm with dSS approximation (O) applying equation (43) with A)i = 5.2 x 10 6 m Langmuirian isotherm with dSS approximation (continuous line) applying equation (46) Langmuirian isotherm with semi-infinite diffusion (dotted line) by numerically solving integral equation (7)). Other parameters c(, = 5x 10-4 mol m-3, Dm = 8 x 10 10 m2 s-1, Kn = 2 x 10-5 m, k — 5 x 10 4 s 1, ro = 1.8 x 10 6 m, r0 + <5M = 10 5 m, KM — 2.88x 10 3mol m 3, Tmax = 1.5 x 10-8 mol m-2...

In principle, the FIAM does not imply that the measured flux. / s should be linear with the metal ion concentration. The linear relationship holds under submodels assuming a linear (Henry) isotherm and first-order internalisation kinetics [2,5,66], but other nonlinear functional dependencies with for adsorption (e.g. Langmuir isotherm [11,52,79]) and internalisation (e.g. second-order kinetics) are compatible with the fact that the resulting uptake is a function (not necessarily linear) of the bulk free ion concentration cjjjj, as long as these functional dependencies do not include parameters corresponding with the speciation of the medium (such as or K [11]). 

In the droplet drag sub-modelT572 598 the effects of droplet distortion and oscillation due to droplet-gas relative motion on droplet drag coefficient are taken into account. Dynamical changes of the drag coefficient with flow conditions can be calculated with this submodel. Applications of the sub-models to diesel sprays showed that... 

Barlow, R. S., N. S. A. Smith, J.-Y. Chen, and R. W. Bilger (1999). Nitric oxide formation in dilute hydrogen jet flames Isolation of the effects of radiation and turbulence-chemistry submodels. Combustion and Flame 117, 4—31. 

Desjardin, P. E. and S. H. Frankel (1996). Assessment of turbulent combustion submodels using the linear eddy model. Combustion and Flame 104, 343-357. 

Because of the dominance of distributed sources over local single sources in the production of photochemical oxidants, point-source models are not discussed here. Related research regarding the measurement of diffusion or the development of atmospheric chemical submodels are not emphasized. Giapter 2 is devoted to the chemical processes that govern atmospheric transformation and removal, and this aspect of the models is not repeated here. 

Predictive capability through integration of submodels for items 1 -9... 

To summarize, to properly model liquid water transport and ensuing flooding effect on cell performance, one must consider four submodels (1) a model of catalytic surface coverage by liquid water inside the catalyst layer, (2) a model of liquid water transport through hydrophobic microporous layer and GDL, (3) an interfacial droplet model at the GDL surface, and last (4) a two-phase flow model in the gas channel. Both experimental and theoretical works, in academia and industry alike, are ongoing to build models for the four key steps of water generation, transport, and removal from a PEFC. 

Submodel for the Grate for Flow Simulations of Grate Fired Furnaces , presented at Swedish-Finnish Flame-day, 30 Sept, Vaxjo, Sweden, (1999)... 

---