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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/42765

Title: 超超臨界系統試驗分析之VB程式計算
VB Program of Thermal Analysis on an Ultra-Supercritical Experimental Apparatus
Authors: Lan, Yuan-Bo
Contributors: NTOU:Department of Mechanical and Mechatronic Engineering
Keywords: 傳熱惡化;總括熱傳係數;超臨界水;VB程式
heat transfer deterioration;overall heat transfer coefficient;Supercritical-water;Visual-Basic
Date: 2014
Issue Date: 2017-05-24T08:23:21Z
Abstract: 本研究針對臺電「超超臨界水質與材料試驗設備」進行改裝評估以及性能分析,主要分為三部分,第一部份為熱交換器熱傳性能分析,由已知的熱交換器尺寸與實驗量測進出口溫度數據,建立一套計算程式,計算在穩態或暫態時的熱傳性能,結果並加以比較。第二部分為臺電新增鍋爐管熱傳惡化實驗之先期評估,並檢索世界各國實驗設備及結果作為建置參考基準。第三部分為傳熱管與環管熱傳特性研究,以現有的傳熱管尺寸和參數以及模擬燃料棒在環型通道傳熱情形,經計算程式來預測出口溫度,避免爐管末端高溫過熱燒毀。 首先本研究分析3組實驗數據,在熱傳分析先進行能量平衡由於HE1與HE2之結構管徑相同,故可將HE1與HE2串聯為一組大型的熱交換器進行能量平衡,接著再進行理論值之總括熱傳係數計算並與實驗值做比較,其平均誤差分別為68%、39% 與11%,在低壓低流量下,量測誤差較大,而且熱傳效果較差。 從各國實驗設備及結果可發現,在臺電設備中壓力及溫度需求上是足夠的,目前須建立測試主體之電力供應、管件配管接頭以及熱電偶佈置裝置,另外在試驗空間足夠下,可將測試主體與現有沖蝕試驗做並聯使用。 最後,理論研究裸管和環管在亞臨界及超臨界壓力條件下,透過改變壓力、質量流率及外壁熱負荷,來探討熱傳特性。結果顯示傳熱係數起始上升緩慢,然後通過擬臨界溫度區域後急劇下降,導致傳熱惡化。 關鍵字:傳熱惡化、總括熱傳係數、超臨界水、VB程式
This study focuses on the thermal analysis of "Ultra-supercritical water and material tested equipment" established by Taipower Company to execute erosion experiments. This paper is consisted of three parts. The first part is to investigate the efficiencies of the heat exchangers. According to the size in each heat exchanger, a computing program coded in Visual-Basic is developed including steady and transient states to calculate the heat transfer performance depending on the measured inlet and exit temperatures. The second part is a pre-assessment of the experimental equipment observing the heat transfer deterioration of boiler tubes for the Taipower’s future supercritical water power plants. The third part is the simulation of bare and annulus tubes with a uniformly heated wall. In a same way, a computing program is used to predict the outlet temperature to avoid overheat depending on the flow rate and the applied power. In the first part, three groups of experimental data are analyzed. Due to the same structure in HE1 and HE2, they can be taken as a combined exchanger during the analysis. Followed by the theoretical formulation, the overall heat transfer coefficients are then calculated and compared with experimental values. The error was found to be around 68, 39 and 11% respectively. This deviation is suspected to the low values of pressure and flow rate during the tests. Referencing the facilities in many foreign countries, the suitable sizes of test piece and the installation of thermocouples are recommended. The operating condition including temperature, pressure, mass flux as well as power supply is all investigated which provides Taipower Company to construct the test apparatus. Finally, a theoretical study is conducted under subcritical and supercritical pressure conditions by varying the pressure, mass flux, and heat flux applied at the wall. The case covers both the normal tube and annulus tube. It reveals that the heat transfer coefficient increases slightly and then drops abruptly at the neighborhood of the pseudo-critical temperature region which may lead to heat transfer deterioration. Keywords: heat transfer deterioration, overall heat transfer coefficient, Supercritical-water, Visual-Basic
URI: http://ethesys.lib.ntou.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=G0010172012.id
Appears in Collections:[機械與機電工程學系] 博碩士論文

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