レーザ誘起蛍光による旋回流予混合器中の気体混合挙動の可視化  [in Japanese] Visualization of Gaseous Fuel Mixing Behavior in Swirling Flow Premixer by Laser Induced Fluorescence  [in Japanese]

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Abstract

微量のアセトン蒸気をトレーサとして燃料流に混入し,高出力のパルスレーザを用いたレーザ誘起蛍光法を適用し,旋回流を伴う希薄予混合器内の燃料流と空気流の混合挙動計測を可能とする光学系を構築した.これを用いて,主流流れに垂直な断面での燃料流体と空気流体の瞬時濃度分布測定を行った.測定した瞬時濃度分布から燃焼器ノズル出口からの高さが増加するに従い,燃料濃度分布のピーク値は減少し,そのピーク値が半径方向外側へ移動すること,濃度変動強さのピーク値が減少し,その位置も半径方向外側へ移動することを明らかにした.さらに燃料流量を同じに設定し,空気流量と旋回羽根角度を変えた場合には,旋回羽根角度の違いよる旋回流の強さと空気流速による違いの影響により,測定高さが同じ位置で,空気流速が大きく旋回羽根角度が小さい場合に最も半径方向内側に濃度変動強さのピーク値が見られた.

One of the most promising approaches to reduce NOx emissions is based on the adoption of lean premixed flames. It is needed to obtain the ideally homogeneity of the air/fuel mixture. This study is aiming to clarify factors that have influence on mixing process of gaseous fuel with air by analyzing the instantaneous concentration of non-reactive fields of mixed gaseous fuel by laser-induce fluorescence (LIF). We showed usefulness of the acetone-LIF instantaneous measurement method to visualize instantaneous mixture field of gaseous fuel and air in swirling flow field using a high power laser system. Instantaneous concentration distributions using LIF show that a peak concentration decreases and the location moves outward with increase of height from exit of the fuel nozzle by swirling flow. It is clarified that deviation of concentration fluctuation decreases and the peak location moves outward as the height increases. It is indicated that characteristics of instantaneous concentration distributions with parameters of air ratio and vane angle.

Journal

  • Transactions of the Visualization Society of Japan

    Transactions of the Visualization Society of Japan 28(11), 86-93, 2008

    The Visualization Society of Japan

Codes

  • NII Article ID (NAID)
    130004955837
  • Text Lang
    JPN
  • Data Source
    J-STAGE 
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