2023-01-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/652039本計畫透過將液態氮注入裝有熱傳流體的鍋爐中產生高壓流體,希望藉此將液態氮轉化為超低溫發電系統中的工作流體。為提升系統效能,本計畫專注於提升液態氮注入鍋爐後,鍋爐增壓的幅度。為此,本計畫將致力於在鍋爐中注入最多量的液態氮,藉此提高增壓幅度。為增加液態氮的注入量,本研究將致力尋求維持液態氮射流穩定性的方法,藉此減少射流表面積、降低液態氮進入鍋爐後的暫態熱傳,進而延緩鍋爐增壓的速度。本研究為此提出一系列實驗專題,包含氣體環境中的液態射流、在不互溶液體中的液態射流,以及在液體中的氣態射流。穩態與暫態射流的行為都將在這些實驗中被仔細檢視。為對實驗進行量化分析,本計畫並將進行熱力學與計算流體力學模擬。熱力學模擬旨在預測鍋爐壓力,計算流體力學則將被用來預測射流的流動行為。透過這些研究專題,本計畫將找出注射液態氮的最佳方法。同時,本研究並將彙整各種射流在不同物理條件下的實驗觀察結果,進一步歸結出各種射流在個條件下,動態反應的對應關係。除了有助於發展超低溫發電系統之外,這些結果更將為任何需要精準控制射流行為的應用提供寶貴的技術資訊。 In this project, liquid nitrogen (LN) is injected into a boiler partially filled with a heat transfer fluid to pressurize the boiler. The purpose is to turn LN into the working fluids for a cryogenic power system. To optimize the system, this project aims at maximizing the boiler pressure head due to the injection of LN. For this purpose, the focus of this study is to maximize the quantity of LN that enters the boiler. To inject the largest amount of LN, this project examines the methods for stabilizing the injected LN jet, thereby minimizing the surface area of the jet, reducing the transient heat transfer and retarding boiler pressurization. Experiments are proposed to examine the stability of a liquid jet in a gas, a liquid jet in an immiscible liquid, and a gas jet in a liquid. Both steady and pulsed jets are examined in detail. To facilitate quantitative analysis of the experiments, thermodynamic and fluid dynamic simulations are proposed. The thermodynamic simulation is meant to predict the pressure created by LN injection. The fluid dynamic simulation, on the other hand, supplies detailed information for examining the dynamics of jets. With these studies, optimal method(s) for LN injection shall be revealed, and the correspondence between gas and jets under different physical conditions shall be mapped out. These results shall benefit the development of a cryogenic power system. Additionally, the results may provide useful information for application that require precise manipulation of a jet in an immiscible surrounding fluid.射流;穩定性;多相流;液態氮;超低溫儲能;jet; stability; multi-phase flow; liquid nitrogen; cryogenic energy storage