丁坝断面流量重分配的试验研究

各种型式的丁坝，在航道整治工程中，被广泛应用．其作用主要有束水、分流、挑流、护岸及改善航行水流条件．丁坝它能调节坝周泥沙的冲淤变化，刷深航槽，稳固河岸．本文通过对在非淹没条件下，正挑丁坝孔口断面的流速分布，及丁坝阻水流量的再分配进行了分析研究．该项试验研究成果在航道整治工程设计中，有较大意义和广泛的应用价值．

分期导流围堰进口断面的流量重分配试验

采用水槽试验，通过观测分析不同围堰束窄度下其进口断面垂线流速分布和水深变化，对围堰遮掩部分的水体在过水断面上的流量分配进行研究，给出了围堰进口断面的阻水流量与束窄度之间的关系以及在断面上的分配规律。研究表明：围堰进口断面的阻水流量随束窄度增加而增加，两者成正比关系；阻水流量由围堰转角向对岸递增分配，有围堰岸各流带的分配率卢变化范围为3.2％-16.4％，无围堰岸β变化范围为20.7％-41.2％。所得结论可为在通航河流上进行分期导流不过水围堰方案布置提供理论依据。

桩柱透水丁坝的局部水头损失试验

作为一种新型河工建筑物,桩柱透水丁坝对局部水流的影响亟需可靠的定量研究.为此,结合理论分析和水槽试验对其局部水头损失进行探讨.首先,应用平面绕流与旋涡理论阐明其局部水头损失的机理,导出了桩柱透水丁坝局部水头损失系数与阻水流量的关系式.而后利用已有的桩柱透水丁坝阻水流量计算公式结合试验资料,得到了计算单个桩柱透水丁坝在非淹没状态下局部水头损失系数的经验公式,该公式计算值与实测值符合良好,可为透水丁坝水力特性的进一步研究提供参考依据.

Experimental study of the flow and heat transfer of a gas–water mixture through a packed channel

Waste heat recovery from the flue gas of gasfired boilers was studied experimentally by measuring the flow and heat transfer of air and water through six kinds of packing with saturated humid air as the simulated flue gas.The experiments measured the effects of inlet air temperature, inlet air velocity and circulating water flow rate on the flow and heat transfer. The results show that higher inlet air temperatures and lower inlet air velocities lower the flow resistance and increase the heat transfer coefficient. The stainless steel packing had better surface wettability and larger thermal conductivity than the plastic packing, which enhanced the heat transfer between the water and the saturated moist air. When both the flow resistance reduction and the heat transfer enhancement were considered, the experimental results gave an optimal packing-specific surface area. A packed heat exchanger tower was designed for waste heat recovery from the flue gas of gas-fired boilers based on the experimental results which had better flow and heat transfer characteristics with lower pump and fan power consumption, more stable system operation and less thermal fluctuations compared with a non-packed heat transfer system with atomized water.