書報討論 2022/5/26:Ph.D student report

  • 2022-05-25
  • 機械系網管
(5/26)下午 3:30-5:20pm 的書報討論, 講者是 博士生進行論文報告 。
講題和順序如下：
  • 陳俊霖 ( 廖英皓老師  )"Effects of an Annular Plasma Actuator Embedded in a Bluff-body Burner on the Non-premixed Jet Flame."
  • The present study is to experimentally investigate the impact of an annular plasma actuator, equipped on a bluff-body combustor, on the non-premixed propane flame. The dielectric-barrier discharge (DBD) actuator is operated with AC sine wave, creating an inward flow to the jet flame. This study contains two pieces: one is to explore the influence of plasma actuator on flow control, and the other is to discover the effects of DBD actuator on flame structure. Results of Schlieren imaging system and particle image velocimetry (PIV) show that the fuel jet, at low Reynolds number, is more susceptible to develop into turbulence and a vortex ring is generated downstream of the bluff-body when the actuator is activated. In flame analysis, results indicates that the induced vortex ring can enhance the flame stabilization and the lifted flame would reattach to the nozzle due to the reduction of the axial local flow velocity. At the final, flame describing number (FDN) is employed to characterize the response of propane flame with plasma actuator and FDN is decreased with larger Reynolds number because the impact of the vortex ring on propane jet flame is less significant.
  • 邱伯縣 (  吳宗信老師   )"Surface Treatment for Improving Adhesion on Polymer by Applying Atmospheric Pressure Plasma Jet"
  • To improve adhesion on the polymer sheets, atmospheric pressure plasma jet (APPJ) was applied to modify the surface of the polymer sheets. A hemi-wicking phenomenon was observed on the hydrophobic sanded surfaces of polypropylene (PP), polyethylene terephthalate (PET) and polyethylene (PE) sheets after APPJ was used to treat a limited area of the sanded polymer surfaces. Such hemi-wicking is triggered by the plasma activation and is different from the traditional hemi-wicking, which is achieved purely by the surface topography.
    Surface analyses by X-ray photoelectron spectroscopy (XPS) and water contact analysis (WCA) show that the combination of sanding and plasma treatment increased the oxygen-to-carbon ratio, which is highly beneficial for surface hydrophilicity. The shear stress tests show that the combination of sanding and plasma treatment can enhance the shear stress by 125%, 95%, and 296% on the bonding PP, PET, and PE films, respectively.
    The study shows that the newly developed technique by combining the sanding and plasma processing for polymers could be a potentially useful method in future industry applications.
  • 賴楷元 （ 劉耀先老師 ）"低溫餘熱回收發電系統設計分析"國內工業餘熱熱源變異性高且存在眾多低溫熱源場址，單以有機朗肯循環(Organic Rankine Cycle)機組特性，無法完全回收可用熱能，以致於效益不足，難以普遍推廣。開發高取熱量及發電量的循環發電系統，將有助於推升使用效益，使原先不具備廢熱回收效益的低溫場址，有重新評估經濟效益的機會。本研究首先根據冷熱源型態與關鍵元件之理論公式建立了三邊閃蒸循環(Trilateral Flash Cycle, TFC)、穿臨界有機朗肯循環（Transcritical Organic Rankine Cycle, TRC）及部份蒸發循環PEC(Partially Evaporating Cycle )熱力學模型，並設定熱源端可容許之最小夾點溫度差為5⁰C，藉由夾點的觀察來調整工作流體蒸發溫度與質量流率，在此基礎上提供了一種找出最佳設計點及其操作條件的方法，並比較各循環系統在淨發電功率、熱效率與膨脹比之關係。
    研究中首先計算R245fa, R134a, R236fa, R1233zd等不同工作流體在預設熱源條件下各循環之設計點；初步分析，三邊閃蒸循環在低溫熱源（<80°C）的取熱量約為有機朗肯循環的1倍，淨功率輸出高約30%。此外，部份蒸發循環系統能夠在發電功率與熱效率僅降低3%的情形下，降低膨脹機膨脹比50%。本研究將依據設計點所計算出之體積流率和熱交換量來進行關鍵元件的選型跟系統的匹配，再配合實驗室冷、熱源條件，進行設計點以及離點性能測試。藉以建置性能資料庫，包含系統性能、膨脹發電機組效率、昇壓泵效率、以及熱交換器熱傳性能，以釐清各循環系統運轉模式與特性。最後再將測試結果回饋至系統設計與分析模式，修正系統模式。
  • 佳鋐 (  陳慶耀老師   )"Research on Jet Flow Field of Magnetohydrodynamics Propulsion System"
  • 磁流推進器，是一運用磁流體力學(Magnetohydrodynamics, MHD)之概念作為主要原理設計之推進器，透過將電能轉換為動能，透過流體運動的反作用力以推動船舶前進。在導電流體或電解質中，放置兩電極板，一為正極一為負極並供應電能會使流體發生電化學反應，使正負電極板上產生電解反應，而反應中之自由電子會於流體中在兩電極間移動，並於此區域產生電場。而透過此電場與推進器內之正交磁場相互作用，即可產生勞倫茲力(Lorentz force)，使得導電流體被向外排出推進器。
  • 黃瑞宇 (  李安謙老師   )"Acceleration-based Parametric FIR Filtering Technique for Motion Planning"
  • There are mainly two motion planning schemes: acceleration/deceleration before interpolation (ADBI) and acceleration/deceleration after interpolation (ADAI). ADBI can generate interpolation commands without contour errors, but suffers from non-continuous velocity jumps when passing through corners. On the other hand, ADAI can pass through corners smoothly, but suffers from contour errors in circular motions. Moreover, all the proposed ADAIs use velocity-based FIR filtering methods (V-FIRs), and cannot process different target velocities and kinematic constraints. To overcome the restrictions in V-FIR, an acceleration-based FIR filtering method (A-FIR) is proposed. In addition, a parametric acceleration/deceleration interpolation (PADI) scheme is proposed to combine the advantage of ADBI and ADAI. The PADI can pass through corners smoothly like an ADAI, and, after passing through corners, generate interpolation commands without contour errors like an ADBI. The proposed acceleration-based parametric FIR filtering technique shows many advantages when compared to traditional schemes. This scheme provides a new way of interpolation and has great potential in motion planning.
  • 因疫情影響，此書報討論將於線上舉辦，歡迎各位加入：
  • https://teams.microsoft.com/l/meetup-join/19%3AAHmJ-1z2CKVby4W8d2QLqfiAi76bN7WTolXvWvvxBlM1%40thread.tacv2/1650428663661?context=%7B%22Tid%22%3A%2280a9abdb-7cef-443c-b040-3f8e75e9232e%22%2C%22Oid%22%3A%2242bfe06c-d7a4-481e-807c-8ea044748226%22%7D