摘要

本實驗是模擬實際燃氣輪機渦輪葉片之前端位置(leading-edge egion)
，利用暫態液晶影像技術來探討在不同旋轉數下，單噴流衝擊在平滑表面上，觀察其熱傳現象。主要目的在於評估以不同的旋轉數對於平滑旋轉管道內部之熱傳影響。實驗控制的主要參數有：旋轉數(Ω=0rpm、Ω=30rpm與Ω=60rpm)，雷諾數(Rej=7000與Rej=9000)及均勻壁溫。
實驗結果顯示，旋轉所造成的離心力以及科氏力，使得噴流彎曲，造成整體的熱傳效果下降，可明顯發現隨著旋轉數增加，平均紐塞數跟著下降9%。且平均紐塞數會隨著雷諾數的增加而變大14%。

Abstract

The present investigation is performed by repeated experiments to simulate the impingement cooling heat transfer in leading-edge region of gas turbine with thermochromic liquid crystals. The experiments was studied on a rotating square duct without crossflow effect from three different rotational speeds of 0, 30 and 60 rpm. The study covered jet Reynolds number 7000 to 9000 and the rotational speeds from 0 to 60 rpm.

Results are presented and focused on the effect of three different rotational speeds. Nusselt number values increased (up to 14%) with Reynolds number. However, Rotation induced coriolis and centrifuged forces and decreased the Nusselt number values about 9% which is quite coincided with those of previous studies.

目 錄
頁 次
目錄……………………………………………………………………….………i
圖目錄…………………………………………………………………………. iv
表目錄………………………………………………………………………… vii
符號說明……………………………………………………………………viii
論文摘要(中文)……………………………………………………………x
論文摘要(英文)………..…………………….……………………………xi

第一章 緒論………………………………………………………………1
1-1 前言………………………………………………………………1
1-2 背景與目的………………………………………………………1
1-3 文獻回顧…………………………………………………………2
1-4 研究範圍…………………………………………………………7

第二章 實驗設備………………………………………………………….11
2-1 旋轉及測試系統………………………………………………11
2-2 測試區裝置……………………………………………………12
2-3 高壓空氣供應及壓力、流量控制系統……………………12
2-4 加熱系統…..…………………………………………………12
2-5 溫度量測系統…………………………………………………12
2-6 暗房……………………………………………………………13
2-7 液晶.……………………………………………………………13
2-8 影像擷取系統………………………………………………13

第三章 實驗量測方法及步驟…………………………………………16
3-1 實驗量測方法…………………………………………………16
3-1-1 流量量測…………………………………………………16
3-1-2 溫度量測………………………………….……………17
3-1-3 液晶校正…………………………………….…………17
3-2 實驗步驟………………………………………………………18

第四章 實驗數據處理…………………………………………………20
4-1 細部熱傳係數………………………………….………………20
4-2 局部紐塞數…..…………………………………………………21
4-3 橫向平均紐塞數..………………………………………………21

第五章 誤差分析……………………………………………………….22

第六章 結果與討論…………………………………………………….25
6-1 細部熱傳係數.…………………………………………………26
6-1-1 旋轉對細部熱傳係數之影響.…………………………26
6-1-2 雷諾數對細部熱傳係數之影響….……….……….26
6-1-3 橫向平均熱傳係數與X之關係..……………………26
6-1-4 中心線局部熱傳係數與X之關係..………………..27
6-2 入口及出口溫度與時間之關係...……………………………27
6-3 平均熱傳係數……………………………….………………27

第七章 結論與建議…………………………………………………….46

參考文獻…………………………………………….…………………………47



圖 目 錄

頁次
圖2.1 實驗設備配置圖………………………………………………….14
圖2.2 測試區幾何尺寸圖………………………………………………15
圖3.1 實驗步驟流程圖..……………………………………………19
圖6.1 平滑管道內在Rej=7000，Ω= 0 rpm時之細部紐賽數(Nusselt number) 分佈圖……………………………………….……28
圖6.2 平滑管道內在Rej=7000，Ω= 30 rpm時之細部紐賽數(Nusselt number) 分佈圖…………….………………………………29
圖6.3 平滑管道內在Rej=7000，Ω= 60 rpm時之細部紐賽數(Nusselt number) 分佈圖…………….………………………………30
圖6.4 雷諾數Rej=7000，三種不同的旋轉數對細部紐賽數(Nusselt number) 之影響…………………….………………………31
圖6.5 平滑管道內在Rej=9000，Ω= 0 rpm時之細部紐賽數(Nusselt number) 分佈圖……………………………………….……32
圖6.6 平滑管道內在Rej=9000，Ω= 30 rpm時之細部紐賽數(Nusselt number) 分佈圖…………….………………………………33
圖6.7 兩種不同的雷諾數對細部紐塞數(Nusselt number)之影響..34
圖6.8 靜止平滑管道內在Rej=7000，橫向平均紐賽數(Nusselt number)與X之關係………………..………………………………...35
圖6.9 平滑管道內在Rej=7000，Ω= 30 rpm時，橫向平均紐賽數(Nusselt number)與X之關係………………………………36
圖6.10 平滑管道內在Rej=7000，Ω= 60 rpm時，橫向平均紐賽數(Nusselt number)與X之關係………………………………37
圖6.11 在Rej=7000，不同旋轉數下，橫向平均紐賽數(Nusselt number)與X之關係……………………..…………...………………38
圖6.12 靜止平滑管道內在Rej=9000，橫向平均紐賽數(Nusselt number)與X之關係………………..………………………………...39
圖6.13 平滑管道內在Rej=9000，Ω= 30 rpm時，橫向平均紐賽數(Nusselt number)與X之關係………………………………40
圖6.14 在Rej=9000，不同旋轉數下，橫向平均紐賽數(Nusselt number)與X之關係……………………..…………...………………41
圖6.15 Rej=7000，不同旋轉數下，中心線局部紐賽數與X之關係…………………..………..……..……….……………….42
圖6.16 Rej=9000，不同旋轉數下，中心線局部紐賽數與X之關係… ………………..………..……..………………………..43
圖6.17 入口及出口溫度與時間之關係圖……………………..……44
圖6.18 平均紐賽數與雷諾數之關係，並和先前之研究者相比較…45

表 目 錄

頁次
表1.1 有關旋轉通道衝擊冷卻實驗相關參數比較…………….……..9
表1.2 通道幾何尺寸與相關參數…………………………………….10
表5.1 參數及變數誤差值…………………………………………….24


符 號 說 明

A ：目標壁面的面積
Af ：噴嘴總面積與目標壁面的面積之比值（open area ratio）,
nπ /4A
dj ：圓孔噴嘴直徑
Cp ：比熱
Dh ：水力直徑，2 W H/（W+H）
h ：熱對流係數
kf ：空氣的熱傳導係數
：測試區長度
Νu ：局部鈕塞數
Νur ：旋轉管道之鈕塞數
Νus ：靜止管道之鈕塞數
P ：絕對壓力
R ： 旋轉半徑（=150mm）
Rej ：噴流雷諾數，Vj dj ／ν
ReΩ ：旋轉雷諾數，Ωdj 2／ν
Ro ：旋轉數，ReΩ/ Rej=Ωdj /Vj
t ：時間
Tb ：空氣局部平均溫度（air buck temperature）
Tj ：噴嘴出口溫度
Tw ：壁溫
Vj ：噴嘴出口速度
x ：測向沿出口方向的距離
x/ dj ：無因次沿出口方向的距離與噴嘴直徑之比
Zn ：目標壁面與噴嘴的距離

希臘字母
α ：測試件之熱擴散係數
Δ ：差距
ν ：空氣動黏度係數
：密度(Density)
τ ：杜罕墨重疊原理中之時間步階變化
Ω ：旋轉速度
上標
__ ：平均值

下標
a ：空氣
i : 初始值
j ：噴流
n ：噴嘴數目
w ：壁邊
∞ ：主流場
Ω ：旋轉

參 考 文 獻
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