nusselt number 中文意思是什麼

( 2 ) the results reveal that the pre - swirl ratio has a great influence on the flow field of the rotating disk, even greater than the rotational reynolds number, and an initial constant is induced in moment coefficient cm and average nusselt number nuave correlations, which does not exist in the case of without pre - swirl

（ 2 ）分析了預旋系數_ r對該旋轉盤腔流場的影響，定義了一個新的壓力系數c _ p ，該壓力系數c _ p沿徑向位置的變化對特定的旋轉雷諾數re _是一個常數。

By comparing the results with relative experiment data, it is shown that rng k - is more exactly than the other turbulent model. 2 ) the influences of axial inflow position, radial outflow size, rotating reynold number, non - dimensional mass flowrate and axial inflow angle on the flow and heat transfer characteristics were numerically investigated for a typical rotator - stator cavity with axial inflow, radial inflow and radial outflow. the correlations for average nusselt number vs rotating reynold number or non - dimensional mass flowrate were established

（ 2 ）針對一典型的徑向、軸向進氣，徑向出氣的轉-靜盤腔結構，系統研究軸向進氣位置、徑向出口大小、旋轉雷諾數、無量綱質量流量和軸向垂直預旋進氣等對盤腔內流動和換熱的影響，整理出轉-靜盤腔內轉盤平均努謝爾數與旋轉雷諾數無量綱質量流量之間的準則關聯式。

4 ) in a pre - swirl rotator - stator cavities with discrete pre - swirl nozzles and blade - cooling entry holes, the influences of pre - swirl angle and flow parameter on the flow and heat transfer characteristics were numerically investigated. the correlation for average nusselt number vs rotating reynold number or non - dimensional mass flowrate were established. the results show that : advantage of per - swirl inflow is the effect of cooling the blade - cooling entry holes ; pre - swirl inflow increases heat transfer in rotating disk of pre - swirl chamber ; as pre - swirl angle increases, local nusselt number decreases in pre - swirl chamber ; the temperature of stator of inner rotator - stator chamber and per - swirl chamber decreases as rotating reynold number increases ; when the axial mass flowrate maintains constant, heat transfer in the rotating disk of inner rotator - stator cavities does n ' t change as per - swirl mass flowrate increases, while heat transfer in the rotating disk of per - swirl chamber increases ; when the pre - swirl mass flowrate maintains constant, change of the axial mass flowrate has effect on the whole cavity

結果表明，預旋進氣的優點在於增強了葉片冷卻孔附近的對流換熱效果，局部努謝爾數隨預旋角的增大而有所減小；隨旋轉雷諾數的增加，不論是內轉靜腔室還是預旋腔室的靜盤上的溫度都不同程度的降低：當軸向中心進氣質量流量不變時，隨預旋進氣的質量流量增加，內轉靜腔室的轉盤盤面上的換熱基本沒有變化，而預旋腔室的轉盤盤面上的換熱效果增強；當預旋進氣質量流量不變時，軸向中心進氣的質量流量的改變對整個盤腔都有影響。

The blade inner channel cooling is a complex convection - conduction coupling problem. this thesis build a three - dimension. compressible turbulence model, and give a general solve method. with the geometrical model of the glossily rectangle straight channel, the rectangle straight channel with in - line arrays disturb plates, the rectangle straight channel with staggered arrays disturb plates, the rectangle straight channel with slant disturb plates, this thesis compute the flow and heat transfer condition when the cold air path though these channels, and gain the temperature field, pressure field, velocity filed, in addition. this thesis also analyze the influence of the different channel height, the different channel materials, the different channels, and gain the function relation between he nusselt number, friction factor and reynolds number. this thesis is emphasis on the new heat transfer enhancement structure, that is, disturb plates, with the comparison with the glossily channel and channel with pin fins, the heat transfer enhancement effect of the former is better, and the conclusion can be used in the design of aircraft blade

葉片內部通道冷卻是一個復雜的對流?導熱耦合傳熱問題，本文在分析葉片內部通道冷卻的流動與傳熱情況的基礎上，建立了三維、可壓縮紊流的物理模型，得到了通用的求解辦法；利用不帶擾流片的矩形直通道、帶順排擾流片矩形直通道、帶叉排擾流片、帶傾斜擾流片的矩形直通道的幾何模型，計算了冷卻空氣通過這幾種通道時的流動與換熱情況，得到了各種不同情況下計算區域的溫度場、壓力場、速度場；在此基礎上分析了不同的通道高度、不同的葉片通道材質對葉片內部通道冷卻的影響，並整理得到了各種通道形式下，努謝爾數和阻力因子與雷諾數的函數關系；本文重點研究了新型的葉片內部通道冷卻強化傳熱措施?帶擾流片的內部冷卻通道的強化傳熱效果，通過與光滑矩形直通道、帶針肋通道的冷卻效果的比較，表明了這種新型鮚構的優勢，對于葉片內部通道冷卻結構的設計可以起到指導的作用。

Based on the review, the fluid flow and heat transfer in the curved circular and rectangular pipes have been researched by employing perturbation method and numerical simulation with a physical model under the rotational orthogonal curvilinear coordinate in a rotating curvilinear pipe with multi - parameters. we firstly analyzed the fully developed fluid flow and heat transfer, mixed convection heat transfer, the development of flow and heat transfer in the inlet in different cross section ( circular, elliptical, annular and rectangular crossection ). the variations of the secondary flow, axial velocity, distribution of temperature, the friction force on the wall, the ratio of friction factor as well as the nusselt number with different dimensionless parameters had been examined in detailed

本文在總結和分析了一個世紀以來有關曲線管道流動和換熱特性的研究成果的基礎上，以旋轉正交曲線坐標系統下的多參數旋轉螺旋管道中的對流傳熱為物理模型，通過攝動方法和有限體積法，首次對各種截面（圓截面、橢圓截面、環形截面、矩形截面）旋轉曲線管道內充分發展流動的流動結構和傳熱特性（包括耦合對流傳熱特性）以及旋轉曲線管道開口段發展流動的流動結構和換熱特性進行了系統的數值模擬和理論分析，詳細討論了各種無量綱參數對管道內軸向速度分佈、二次流結構、溫度分佈、壁面摩擦力、摩擦系數比以及管道nusselt數的影響，獲得了若干創新性成果。

Secondly, the relation between nusselt number and the local time - averaged velocity and temperature fields of turbulent convection was theoretically induced, which expands the field - coordinated enhancement principle to turbulent convective heat transfer

然後，在理論上導出了紊流對流換熱的整體換熱性能與局域時均速度場和時均溫度場的一般關系式，將對流換熱的場協同強化原則擴展至湍流換熱。

For different f, the effect of curvature and torsion on the flow structure, temperature distribution, the friction factor and nusselt number

不同的f下撓率和曲率對流動結構、摩擦系數和nusslt數的影響不同。

In this paper, the working fluid is air. experimental study of the nine different structure parameters of 3 - d ift with staggered arrangement fins in the reynolds number range of 250 to 30000 is performed to investigate the characteristics of heat transfer and flow friction behavior. analyses and reduces the experimental data by the least square method, obtains the nusselt and fanning friction fitting criterion equations

本文以空氣為工質，在re 250 30000范圍內對九根具有不同肋形結構尺寸的肋叉排三維內肋管的換熱及流動特性進行了研究，並運用最小二乘法分析和處理實驗數據，獲得努謝爾特數，范寧摩擦系數與雷諾數，肋幾何參數的準則方程式。

3 ) a custom filed function module was complied to study the influence of non - dimensional mass flowrate changed with time in stair shape on flow and heat transfer inside rotator - stator cavity with axial inflow and radial outflow. average nusselt number takes on a sharp up - down process when the mass flowrate changes from stabile status as to the following change of flowrate, the average nuselt number changes greatly in the initial stage and then changes gradually

（ 3 ）自編用戶程序模塊，研究在軸向入流、徑向出流的轉-靜盤腔中，無量綱流量隨時間呈階梯型改變對盤腔流動和換熱的影響。當流量從某個穩定狀態改變時，轉盤上的平均努謝爾數會產生一個明顯的上升再降低過程；在每一次流量改變的初始階段，平均努謝爾數存在一個較大幅度的變化。

When the rotation has the same direction with the axial velocity, the effect of rotation enforces the intensity of secondary flow and the heat convection, the friction factor and the nusselt number increases as f increase ; when the rotation has the opposite direction with the axial velocity, the flow structure becomes more complicated, for f = 1. 2, the complicated structure of secondary flow generates, the friction facior and nusselt number almost has the same value of stationary straight pipe

當旋轉方向和主流方向相同時，旋轉的作用加強了二次流的強度，使得管道摩擦系數變大，管道換熱效果增強；當旋轉方向和主流方向相反時，管道內流動結構變化十分明顯， f - 1 . 2時，流動結構最為復雜，摩擦系數降至最低，換熱效果最弱。