当前位置: X-MOL 学术Int. J. Refrig. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
FDM for the freezing process of a slab using integral average properties
International Journal of Refrigeration ( IF 3.9 ) Pub Date : 2020-08-01 , DOI: 10.1016/j.ijrefrig.2020.07.026
S.R. Ferreira

The finite difference method (FDM) was used to calculate the temperature profile of the slab T(x,t) and freezing time (tcalc). The methodology is based on the integral average property (Pav) for each property P(T) (k, ρ, and Cpap), which is the integral of P(T) from the initial slab temperature (T0) up to a reference temperature (Tref), divided by the temperature range (TrefT0). The objective is to obtain an adequate (Tref) and a set of appropriate P(T) for a given set of experimental data. Simulations were performed to test several (Tref), obtaining (tcalc), which was compared with 337 data from the slab freezing process. The principal findings were used to obtain the following parameters: minimum error Emin = -6.71 %, overall mean error Emean = -0.27 %, maximum error Emax = 5.84 %, and standard deviation σn-1 = 1.69 %. When the Biot number is large, Bif → ∞, Tref = Tarith or Tref = T(i) is generally adequate to calculate (tcalc), (Tarith) being the average arithmetic temperature and T(i) temperature at a point (i), respectively. If Bif → 0, Tref = Tcf generally produces good results for (tcalc), (Tcf) being the final temperature in the center of the slab. If the traditional Biot number Bi → 0, the average temperature (Tav) → (Tc), obtained from the analytical solution with the convective boundary condition for a slab, (Tc) being the center temperature. If Bi → ∞, (Tav) → (Ta) + (2/π)(Tc - Ta), (Ta) being the ambient temperature.



中文翻译:

使用积分平均特性的板坯冻结过程的FDM

使用有限差分法(FDM)计算板坯的温度曲线Tx,t)和凝固时间(t calc)。该方法基于每个属性P(T)k,ρCp ap)的积分平均属性(P av),它是从初始板坯温度(T 0)到初始板坯温度(T 0)到P(T)的积分。参考温度(T ref)除以温度范围(T refT 0)。的目的是获得一个适当的(Ťref)和一组给定实验数据的适当P(T)。进行模拟以测试多个(T ref),获得(t calc),并将其与板坯冻结过程中的337数据进行比较。主要发现用于获得以下参数:最小误差E min  = -6.71%,总体平均误差E mean  = -0.27%,最大误差E max  = 5.84%,标准偏差σn -1  = 1.69%。当比奥数大时,Bi f  →∞,T ref  =  T arithT ref  =  T(i)通常足以计算(t calc),(T arith)分别是点(i)的平均算术温度和T(i)温度。如果Bi f  →0,则对于(t calc)(T cf)是板坯中心的最终温度,T ref  =  T cf通常会产生良好的结果。如果传统的毕奥数Bi  →0,则平均温度(T av)→(T c)是从平板的对流边界条件(T c为中心温度)的分析溶液中获得的。如果 →∞,(Ť AV)→(Ť)+(2 /π)(Ť Ç - Ť),(Ť一个)是环境温度。

更新日期:2020-09-15
down
wechat
bug