Backwater-aeration structures formed from composite materials

Abstract

A process-flow diagram of the construction of backwater-aeration regulating structures is developed.Backwater-aeration regulating structures (BARS) formed from flexible materials, which aerate the flow and also partially regulate the upper pool within the range from 0.2 to 1.2 m, can be used to improve the self-purification of small water courses [1]. The water level required for aeration of the flow is maintained in the low-water period, and virtually free passage of the flow is ensured during the spring flood, since the spillway wall is pressed against the bottom of the water course. Some BARS structures have been installed in the discharge channels of the Bagaevsko-Sadkovskaya irrigation system (Bg-SM-5). Since one of the most important characteristics of the discharge channels is their carrying capacity, it is necessary to evaluate the latter after installation of the BARS.In the central portion of the BARS is a new type of flexible spillway with varying geometric parameters. This spillway is reinforced in the lower section, and is free to move in the upper section, depending on the flexibility of the material, flow rate, and water level in the upper and lower pools [2,3]. The discharge may take place both over the crest of the spillway, and also through its lateral sides, thereby increasing the spillway front; this will enhance the aeration efficiency of the water course by providing free access of air to the space beneath the jet.To determine the hydraulic characteristics of the spillway in question, we conducted experimental investigations in the hydraulics laboratory of the Novocherkassk Reclamation Academy (Fig. 1). A model of the flexible spillway was placed in a hydraulic flume 1 m wide, 6 m long, and 0.55 m high. The flexible spillway under investigation with its 600-mm wide threshold was fashioned from a corded rubber material 32 mm thick, and has an open-lining perimeter of 400 mm. The height of the spillway wall was varied within the limits from 115 to 350 mm, and the horizontal projection of the distance from the point where the spillway attaches to its crest -from 250 to 350 mm. The flow rates ranged from 0.005 to 0.035 m 3 /sec. A series of experiments were conducted with and without discharge passed through the lateral sides of the spillway. We investigated regimes where the level of discharge increased, and, conversely, remained steady over the flexible spillway, and also its characteristic geometric and hydraulic parameters. The modeling was car-

Experimental investigations of mobile water-power structures for small water courses

“…Relationship (6) yields rpm on the low side as compared with empirical relationship (1). In this connection, it is necessary to consider the power of the flow against the outlet blade, and include correction factors in calculating characteristics of the full-scale turbine; this will be done in future investigations.…”

“…Small-and micro-power generation may therefore be found useful for power supply to small villages and farms, as well as extraordinary situations in the case of the failure of permanent water-retaining structures after the passage of floods [1].For small water courses, we have developed designs of mobile water-power structures based on lightweight dams formed from polymeric materials, and a portable generating set with a transverse-jet turbine, which create a head of from 1 to 4 m, cover a span of up to 50 m, and ensure a producible capacity of up to 160 kW [2, 3, 4]. As operating experience with lightweight dams that have been used for irrigation in the Kursk Oblast, a stable water supply to irrigation equipment has been provided during the irrigation season at four prepared sites on the Kurits River by the installation of a single dam.…”

“…Small-and micro-power generation may therefore be found useful for power supply to small villages and farms, as well as extraordinary situations in the case of the failure of permanent water-retaining structures after the passage of floods [1].…”

Mobile Derivational Micro-HPP for Reserve Water Supply and Standby Power Service of Recreation Facilities and Harbour Installations of Russky Island

“…The initial position of the coordinate axes for the initial section remains. For upper elastic it is appointed a new coordinate system, the beginning of which goes to the border of the lower elastic [8,10].…”