本文選題：城市熱環(huán)境 + CFD模擬設(shè)定　； 參考：《西南交通大學(xué)》2013年博士論文

【摘要】：過去二十多年來,國內(nèi)外大多數(shù)研究采用RANS兩方程湍流模型和LES模型來研究城市區(qū)域環(huán)境,由于城市區(qū)域環(huán)境的復(fù)雜性和較大的空間尺度,兩種計(jì)算方法需要特別大的計(jì)算機(jī)資源,因此如何能夠快速而又有效地預(yù)測(cè)非等溫城市區(qū)域環(huán)境成為本研究的主要目標(biāo)。本文首先分析目前城市風(fēng)熱環(huán)境的研究方法、城市環(huán)境CFD模擬技術(shù)、建筑外表面對(duì)流換熱系數(shù)以及城區(qū)區(qū)域污染物對(duì)流傳輸?shù)挠绊懙妊芯窟M(jìn)展,提出了本文的主要研究內(nèi)容：(a)提供優(yōu)化的零方程湍流模型(Zero-EQ),(b)研究不同街谷和建筑群分布的建筑外表面對(duì)流換熱系數(shù)分布,(c)證明優(yōu)化的零方程湍流模型以及壁面溫度和對(duì)流換熱系數(shù)組合的邊界條件能夠快速有效地預(yù)測(cè)城市熱環(huán)境,(d)研究城市區(qū)域環(huán)境污染物對(duì)流傳輸?shù)挠绊�。詳�?xì)的研究內(nèi)容如下： 本研究通過研讀大量的參考文獻(xiàn)和歸納總結(jié)長期的CFD計(jì)算經(jīng)驗(yàn),提出了城市區(qū)域環(huán)境CFD模擬設(shè)置常用的設(shè)定方法,包括湍流模型的選擇,數(shù)值誤差的確定,計(jì)算區(qū)域的設(shè)置,計(jì)算網(wǎng)格的劃定,以及計(jì)算邊界條件的設(shè)定等,建立了簡化的CFD模擬設(shè)定分類,提供給研究者一些理論和經(jīng)驗(yàn)的總結(jié)。 本研究選用風(fēng)洞實(shí)驗(yàn)對(duì)零方程湍流模型進(jìn)行優(yōu)化,分析實(shí)驗(yàn)數(shù)據(jù),推導(dǎo)出優(yōu)化的湍流渦粘度表達(dá)式,應(yīng)用新的優(yōu)化的湍流模型與風(fēng)洞實(shí)驗(yàn)數(shù)據(jù)進(jìn)行驗(yàn)證和分析。結(jié)果表明,在同等計(jì)算機(jī)配置下,Zero-EQ能夠比MMK湍流模型快60%以上,是LES計(jì)算所需時(shí)間的1/10,同時(shí)Zero-EQ能較準(zhǔn)確地預(yù)測(cè)多棟建筑周圍流場的分布�？紤]到重復(fù)不同工況風(fēng)洞實(shí)驗(yàn)的局限性,本研究首先選擇RANS兩方程湍流模型來預(yù)測(cè)不同建筑群分布的流場分布,得到不同建筑群基于應(yīng)變率和局部速度大小的渦粘度表達(dá)式(Zero-EQ2和Zero-EQ3)。利用上述風(fēng)洞實(shí)驗(yàn)的研究結(jié)果(Zero-EQ1),選用不同的建筑群分布,對(duì)比三種模型的模擬結(jié)果與MMK湍流模型預(yù)測(cè)數(shù)據(jù)的優(yōu)劣,得到Zero-EQ2和Zero-EQ3比Zero-EQ1更能夠快速有效地預(yù)測(cè)建筑群周圍流場分布的結(jié)論。 本研究利用CFD模擬計(jì)算的方法對(duì)不同城市街谷高寬比(H/W)和不同平面面積密度(λp)建筑群分布(并行式和交錯(cuò)式)的室外表面對(duì)流換熱系數(shù)進(jìn)行研究,推導(dǎo)出不同建筑分布狀況下的對(duì)流換熱系數(shù)表達(dá)式,和選用風(fēng)洞實(shí)驗(yàn)數(shù)據(jù),和現(xiàn)場測(cè)試(賓夕法尼亞州立大學(xué)校園某學(xué)生公寓)數(shù)據(jù),獲取足夠的計(jì)算邊界條件和驗(yàn)證數(shù)據(jù),減少計(jì)算區(qū)域網(wǎng)格,通過設(shè)置對(duì)流換熱系數(shù)和溫度邊界作為壁面計(jì)算條件,來間接驗(yàn)證對(duì)流換熱系數(shù)的準(zhǔn)確性；應(yīng)用零方程湍流模型計(jì)算城市街谷的熱環(huán)境,得到與風(fēng)洞實(shí)驗(yàn)吻合較好的數(shù)據(jù),比RANS兩方程湍流模型快一倍的速度,證明了其在工程應(yīng)用領(lǐng)域的優(yōu)勢(shì),同時(shí)指出零方程湍流模型對(duì)于浮力流動(dòng)預(yù)測(cè)的局限性。另外,本研究中計(jì)算得到的對(duì)流換熱系數(shù)表達(dá)式能夠?yàn)榻窈罄^續(xù)能耗模擬研究提供足夠的研究依據(jù)。 本研究利用以上研究成果：優(yōu)化的零方程湍流模型和建筑外表面的對(duì)流換熱系數(shù),研究二維城市街谷和三維建筑群的熱環(huán)境對(duì)污染物濃度的影響。首先利用RNG湍流模型研究二維城市街谷的不同壁面受熱條件下自然對(duì)流環(huán)境、混合對(duì)流環(huán)境和強(qiáng)迫對(duì)流環(huán)境下的速度分布、溫度分布和污染物分布。由于零方程湍流模型不能較好地預(yù)測(cè)浮力流動(dòng),三維建筑群只選擇強(qiáng)迫對(duì)流為主的熱環(huán)境,選擇入口與壁面溫度差分別為ΔT=0℃和AT=10℃的兩種邊界條件,通過分析建筑群周圍污染物的分布,驗(yàn)證了其快速預(yù)測(cè)污染物分布的準(zhǔn)確性。最后本文選擇成都市蒲江縣壽安鎮(zhèn)的某一生態(tài)建設(shè)項(xiàng)目,根據(jù)當(dāng)?shù)貧庀髼l件,通過研究壽安舊城區(qū)目前城市規(guī)劃情況下的夏季城市熱環(huán)境,分析不同區(qū)域的熱環(huán)境特點(diǎn),提供給新城區(qū)規(guī)劃設(shè)計(jì)一些建議。EnergyPlus能耗計(jì)算最后應(yīng)用于某一學(xué)生公寓建筑,來研究考慮周邊建筑環(huán)境對(duì)流換熱系數(shù)表達(dá)式的實(shí)用性。
[Abstract]:In the past two decades , most of the researches at home and abroad use RANS two - equation turbulence model and LES model to study the urban regional environment . Because of the complexity of urban regional environment and the large spatial scale , the main research contents of this paper are as follows : ( a ) the research methods of urban wind - thermal environment , the CFD simulation technology of urban environment , the surface - facing flow heat transfer coefficient of the building and the effect of convective heat transfer in urban area .

Through studying a large number of references and summing up the long - term CFD calculation experience , this paper presents a common setting method for the CFD simulation of urban area environment , including the selection of turbulence model , the determination of numerical error , the setting of calculation area , the delimitation of calculation grid , and the setting of calculation boundary conditions .

The results show that Zero - EQ is more than 60 % faster than MMK turbulence model , and it is used to predict the distribution of flow field around multiple buildings . The results show that Zero - EQ can predict the distribution of flow field around multiple buildings .

In this paper , the convective heat transfer coefficient of outdoor surfaces of different urban street heights ( H / W ) and different plane area densities ( 位p ) is studied by CFD simulation method . The expressions of convective heat transfer coefficient under different building distribution conditions are derived , and data of wind tunnel experiment data and field test ( a student apartment in Penn State University ) are selected to obtain enough computational boundary conditions and verification data , so as to reduce the grid of the calculation area , and the accuracy of the convective heat transfer coefficient is indirectly verified by setting the convection heat transfer coefficient and the temperature boundary as the wall surface calculation conditions ;
By using the zero equation turbulence model to calculate the thermal environment of the urban street valley , the data with good agreement with the wind tunnel experiment is obtained , which is twice as fast as the turbulence model of the RANS equation , which proves the advantages of the zero equation turbulence model for the prediction of buoyancy flow . In addition , the expression of the convection heat transfer coefficient calculated in this study can provide enough research basis for the future energy consumption simulation study .

In this paper , the effects of thermal environment on pollutant concentration in two - dimensional urban street and three - dimensional buildings are studied by using the above research results : optimized zero equation turbulence model and convection heat transfer coefficient of the outer surface of buildings .
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2013
【分類號(hào)】：X16;TU119.4

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本文編號(hào)：2106836