暴気式の適用範囲と暴気区間について

• 中曽根 英雄

  東京教育大学農学部

書誌事項

タイトル別名

• Appliciable Scope of Equation of Aeration and the Region for Aeration
• Study on the aeration at falls and spillways (II)
• 段落流の暴気に関する研究 (II)

抄録

In a previous paper, an equation for the aeration in case of falling water, such as weir and spillway, has been derived under the condition that the depth of water cushion was sufficient. Here, we inqure whether the equation obtained in the previous paper can be applied or not when the water depth is shallow and the bottom of channel is so deep that entrained air bubbles can not reach the bottom.<BR>Generally, it can be said that weir and spillway are the main equipments of aeration. In this case, it is necessary to determine the length of water cushion throughout the performance of aeration, the optimal depth of water cushion, and its efficiency. The experiment resulted in the following conculusion regarding these subjects:<BR>(1) When the water cushion is in a state as shown in Case I of Fig. 1, the equation of aeration is valid, employing a coefficient η as given in Eq.(7).η=1.41 (Case I in Fig. 1), and η=1 (Cases II, III in Fig. 1).<BR>(2) When the water depth becomes so deep that the entrained bubbles cannot reach the bottom of channel as shown in Fig. 5, an equation is formulated as given in Eq.(8). On the contrary, when the entrained bubbles reach the bottom of channel, then it is enough to put H_d=0.<BR>(3) When weir and spillway are used as an aeration unit, the best depth of water cushion can be calculated from Eq.(12). When the appliciable scope of Eq.(12) is shallower than H₂ (from Eq.(12)), the best depth of water cushion should be H₂.<BR>(4) The length of a region in which aeration is performed is calculated from Eq.(13). Therefore, the re-aeration coefficients of falling water, such as weirs and spillways, are represented by Eq.(15). Both of Eq.(13) and Eq.(15) can be used as the depth of the water cushion only in Case III.<BR>(5) Aeration efficiency of falling water is better than other diffused-air units as shown in Fig. 10.

収録刊行物

• 農業土木学会論文集

  農業土木学会論文集 1975 (59), 23-29,a1, 1975

  社団法人 農業農村工学会

詳細情報

• CRID: 1390282679519742976
• NII論文ID: 130004347038
• DOI: 10.11408/jsidre1965.1975.59_23
• ISSN: 18847234
• ISSN: 03872335
• データソース種別:
  • JaLC
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可