【正文】 This phenomenon renders the air distribution in the room ineffective in removing the heat load and, as a result, the thermal fort in the occupied zone deteriorates. Here again there is a scarcity of design data, particularly for nonisothermal air jets. Air distribution problems, such as those discussed here, are most suitable for numerical solutions which, by their nature, are good design optimization tools. Since most air distribution methods are unique to a particular building a rule of thumb approach is not often a good design practice. For this reason, a mockup evaluation has so far been the safest design procedure. Therefore, numerical solutions are most suitable for air distribution system design as results can b readily obtained and modifications can be made as required within a short space of time. Because of the plexity of the air flow and heat transfer processes in a room, the numerical solutions to these flow problems use iterative procedures that require large puting time and memory. Therefore, rigorous validation of these solutions is needed before they can be applied to wide ranging air distribution problems. In this paper a review is given of published work on numerical solutions as applied to room ventilation. The finite volume solution procedure which has been widely used in the past is briefly described and the equations used in the kε turbulence model are presented. Numerical solutions are given for two and threedimensional flows and, where possible, parison is made with experimental data. The boundary conditions used in these solutions are also described. 練習(xí)4。 如何寫論文的展開部分(Approach), 結(jié)果和討論(Results and Discussion) 材料和方法部分對(duì)于以實(shí)驗(yàn)為主的研究論文，該部分往往位于論文展開部分的前面。對(duì)于實(shí)驗(yàn)，描述應(yīng)盡可能詳細(xì)。詳細(xì)的程度應(yīng)使別的研究者可以重復(fù)你的實(shí)驗(yàn)，對(duì)難以重復(fù)的實(shí)驗(yàn)可評(píng)價(jià)你的實(shí)驗(yàn)。這一部分經(jīng)常采用小標(biāo)題，如：subjects, apparatus, experimental design, and chemical synthesis。在這一部分，你應(yīng)當(dāng)說明：(1) 你所用的材料和化學(xué)藥品的名稱；(2)實(shí)驗(yàn)條件；(3)實(shí)驗(yàn)儀器；(4)實(shí)驗(yàn)方法和步驟。 原理和理論模型部分對(duì)于理論分析和數(shù)值計(jì)算為主的研究論文，該部分往往位于論文展開部分的前面。一般首先用數(shù)學(xué)方法描述所討論的問題，如列出控制方程、邊界條件和初始條件。為簡化問題并突出問題本質(zhì)，常需對(duì)問題進(jìn)行合理假設(shè)。這部分會(huì)引入一些方程、格式、邊界條件和初始條件，下面通過一些例子說明其經(jīng)常采用的表達(dá)方式。例1[5]DEVELOPMENT OF MODELThe model assumes that VOCs are emitted out of a single uniform layer of material slab with VOCimpermeable backing material, and a schematic of the idealized building material slab placed in atmosphere is shown in . The governing equation describing the transient diffusion through the slab is （1）where C(x,t) is the concentration of the contaminant in the building material slab, t is time, and x is the linear distance. For given contaminant, the mass diffusion coefficient D is assumed to be constant. The initial condition assumes that the pound of interest is uniformly distributed throughout the building material slab, ., t=0 （2）where L is the thickness of the slab, and C0 is the initial contaminant concentration. Since the slab is resting on a VOCimpermeable surface, the boundary condition of the lower surface of the slab is (3)A third boundary condition is imposed on the upper surface of the slab () (4)where hm is the convective mass transfer coefficient, m/s；Cs(t) is the concentration of VOC in the air adjacent to the interface。 mg m3。 C165。(t) is the VOC concentration in atmosphere, mg m3. It should be mentioned that almost all the physically based models in the literature assumed Cs(t)= C165。(t), . implied that hm is infinite, (Dunn, 1987。 Clausen et al., 1991。 Little et al., 1994). Obviously, the case assumed is a special case of equation (4). Besides, equilibrium exists between the contaminant concentrations in the surface layer of the slab and the ambient air, or (Little et al., 1994) (5) where K is the socalled partition coefficient.C(L,t)Cs(t)LC165。(t)xC(x,t) building material air interface Schematic shown of a building material slab in atmosphere.The solutions to equations (1)(5) derived by us are as follows (6)where βm (m=1,2,…) are the positive roots of (7)Equation (6) gives the contaminant concentration in the building material slab as a function of distance from the base of the slab, and also of time. Thus, VOC emission rate per unit area at instant t and VOC mass emitted from per unit area of the building material slab before instant t m(t) can be respectively expressed as follows (8) dt （9）下面是引出公式的一些例句、句型：。Plugging these values into....It yields following inequality:From Eqs. (1), (2) and (5) it follows that A may be expressed as Equation (1) relates A and B.Then the solution to equation (1) isCombining equations (1) and (2) givesUsing the boundary conditions (3) and (4), eq.(1) can be written as:Considering the boundary conditions (3), (4) and (5), the temperature distribution is:Assuming a relationship between A and B of the formExpression (1) is applicable only for angles from 0 to θ, whereθsatisfies the condition …Assuming steadystate conditions, governing equations are: …這里需要注意的是，對(duì)公式中出現(xiàn)的符號(hào)有兩種解釋方式，其一是在公式下，用where引出解釋，其二是在論文中(一般在引言前)用符號(hào)表(Nomenclature , Notation, Symbols)說明。 一般當(dāng)符號(hào)比較多時(shí)采用后者。需注意的是一旦采用后者，公式中出現(xiàn)的符號(hào)可不再解釋，避免重復(fù)。后者的例子如下：例1[2]Nomenclature specific surface area of packing (m2/m3) wetted surface area of packing (m2/m3) specific heat (kJ/kg oC) diffusivity (m2/s) nominal size of packing (m) gas phase mass transfer coefficient (kmol/m2 s) liquid phase mass transfer coefficient (kmol/m2 s) superficial air (gas) flow rate (kg/m2 s) acceleration of gravity (m/s2) gas side heat transfer coefficient (kJ/m2 s) gas phase mass transfer coefficient (kmol/m2 s Pa) liquid phase mass transfer coeff