Zhu Shihong, Niu Xingqiang and Yang Chun
Yangitze River
Scientific Research Institute, Wuhan, 430010, China
Tel:86-27-82829760 Fax:86-27-82633828
Abstract: Yantan Ship Lift is the largest ship chamber in China. In prototype test, it is mainly measured that water wave in ship chamber、rope force、wave stir in pool and water velocity in the mouth、the tension change of moment steel wire、the oscillate of ship chamber and drop door.
Keyword: vertical ship lift, ship chamber, drop door, water wave, rope force
Yantan water power plant is located at the middle reaches of Hongshui River, the dam high is 110 meters long, the total storage capacity is 33.5 billion cubic meter. The workshop is located at the right bank of the river, left bank standing the building which is opened to navigation, seven flooding dams located in the middle of river. The vertical ship lift which use the vertical reel crab、balance in part and ship chamber in water is adopted to the navigating building. The ship lift is designed for ships that can carry 250 tons goods, whose lift height is 68.5 meter. It is the characteristic of ship lift that the high operation-speed and the littler need of water. That is very economical for the water power plants whose main task is to generate electricity. However, because of the technical complexity, it is fewer builded inside and outside China. Although embedded research has been carried out to solve many kinds of technical problems by model tests, the prototype observation is very important it to collect data for practical operation.
It is mainly observed that water wave in ship chamber、rope force、wave stir in poor and water velocity in the door、the moment change of steer wheel、the oscillate of ship chamber and drop door.
The available scale of ship chamber is 40m×10.8m×1.8m. From upstream to downstream, seven pressure sensors are installed in turn on the side- wall to observe the water wave in chamber, whose serial number is A1 to A7 (Fig.1).
Rising or depressing the ship chamber (in air) in gear, the water wave is little. Because of the Aeolian infection, the max value is close to 0.1m.
In every kinds of operation condition, the water surface wave is greater when the chamber meets upper gate bay. When the water level of chamber is approximately equal to that of the upstream and turning on the drop down door, firstly the water of chamber or upstream sea-route flows to the door, then due to the inertia effect, the water of sea-route comes into the chamber. Collectively, the value change of every measure point is consistent, the nearer the point is next to downstream, the greater is the change of water body. When the water level of chamber exceeds that of the upstream and turning on the drop down door, firstly the water of chamber comes out. When the water level of chamber next to downstream is less than that of upstream, the sea-route water comes into chamber immediately, and the greater the water body is, the longer the lasting time is and the max wave values of every measure point are near 0.2m. When the water level of upstream is 0.1m more than that of the chamber and turning on the drop down door, the water wave of chamber reaches to the max value(fig 2). At this time, because the water body beside chamber comes into chamber, longitudinal movement appears. When it arrives the downstream door, because the doors hold it up, it returns to upstream and joins into the water body coming from the upstream, wave peak value reaches to the max value of 0.3m approximately at A7 measure point.
On test, the rope force (of ship which can carry 90 ton goods) is measured by four measure points (Fig 1), the force of every point is broken down into longitudinal、transverse and vertical direction respectively. Because the bargain angle of rope and vertical direction is large, the vertical force is little and will not be discussed here. In order to be consistent with fact, we join the force of two point upstream into Fup, and that of downstream into Fdown.
In every kinds of operation, when the chamber meets upper gate bay or moves slimly to downstream, the most disadvantage condition of rope force happens. Otherwise, the force value is in the design permission range. When the chamber meets the upper gate bay and the water level of upstream exceeds the water level of the chamber 0.1m, the max rope force of longitudinal direction is 8.0kN and it is beyond the design permission range. On the condition, the max rope force of transverse direction is 1.5kN and it is in the design permission range. When the chamber moves slimly to downstream, finding the chamber moved up 0.13 m, the water body of the chamber quickly flows out, the max peak value of water level change is 0.4m in the beginning. The longitudinal force reaches its largest value when the water level change reaches its peak. On the condition, the max rope force of longitudinal direction is 7.4kN and it is beyond the design permission range, the max rope force of transverse direction is 2.4kN and it is in the design permission range.
When the velocity by which the chamber comes in or out of water increases, so increases the velocity of water in the mouth. When the velocity by which the chamber is raised into the water is 1.8m/min and 2.2m/min, the max value of velocity in the mouth is 0.92m/s and 1.36m/s respectively. When the velocity by which the chamber is raised out of water is 1.8m/s and 2.2m/s, the max value of velocity in the mouth is 1.69m/s and 2.67m/s respectively. Because the way of the downstream water exchange with the pool is various, so in the condition of same exchange speed, the water velocity in the mouth of the chamber raised out of water is greater than that of the chamber raised into water. When the chamber is raised into water, it pushes water aside, making the water level of pool ascend, then water flows from pool to the downstream sea-route. When the chamber is raised out of water, the water level of pool falls, water flowing from the downstream sea-route to the pool. Because the water level value of falling is greater than that of ascending(refers to the next period)and the water body of the downstream sea-route is great, correspondingly its inertia is great, comparing with the water body flowing from the pool to the downstream sea-route, the water body volume flowing from the downstream sea-route to the pool is greater, so the velocity in the mouth is bigger.
When the chamber is raised into or out of water, with its increasing velocity, the wave in the pool and of downstream increase too. While the hemline of the chamber comes into water, the water of pool begins to ascend. Then because the velocity of the chamber starts to decrease, it begins to fall. When the velocity of the chamber exceeds 2.2m/s, even if the water level falls because of the velocity decreasing, the velocity is still too great and the water level can’t return to the previous value. When the chamber stops moving, the water of pool still flows to the downstream sea-route because of its inertia, making the water level of pool lowering. Hereafter, the water of the downstream sea-route swarms into the pool, little by little, the water level returns to the initiative value. During the course of the chamber raised out of water, as soon as the chamber is raised, the water level of the pool falls quickly. The greater is the velocity by which the chamber is raised out of water, the greater is the falling water level value. Then, the water body of the downstream sea-route swarms into the pool and the water level starts to rise. Because of its inertia, the ascending value is greater than the falling value. When the hemline of the chamber comes out of water, the water body of the downstream sea-route still swarms into the pool with its inertia. Hereafter, the water level waves round the initiative value. When the velocity of running out water exceeds 2.2m/s, the moving water brings along the sand in the bottom of the mouth door，making the water surface muddy.
There are sixty steel wires in the Yantan ship lift and forty-eight of those is moment steel wires, sixteen is balance steel wires. The lifting moment steel wires are an important part of the main lift. Normally, the water is 1.8m deep, the total pull force that moment steel wires receive is about 11370kN. Considering the oscillation of the chamber in operation, the moment tension would exceed 11400kN. Particularly, on the condition that the chamber is stopped quickly when it operates with high speed, the tension would obviously increases because of the gravity inertial of water body and the chamber equipment.
By adjustable screw, the moment steel wires are joined with oil press cylinder that is used to adjust. In test, the tension of moment rope reacts through the screw. When the water is 1.8m deep, the average value of tension is 244kN. When the chamber is stopped for the reason of accident during it is running down, the average value of tension amplitude is 49.1kN, the max value of amplitude reaches to 58.3kN. When the chamber operates normally, even if there is one steel wire broken, around the broken rope, the tension of other steel wires reach to the max value, and then is quickly equalized. When the chamber is adjusted to be level in the static station, the tension of steel wires standing on high side reduces and in low side the tension of steel wire increases ,but it quickly is equalized.
When the chamber is quickly stopped for the reason of accident during it is running down, the max swing value of vertical displacement can reach 20mm and the oscillation phase is consistent at every point, but the swing has 4mm difference and the oscillate acceleration can reach 0.85m/s2.
In the other condition, the chamber moves smoothly and the oscillation swing is little. When the drop door located in upward or downward of chamber closes or opens, it moves calmly. The oscillation is very little, only on the moment that the door opens or closes, there is a little oscillation.
In a word, inside the research, according to the prototype observation data: during the whole course of the chamber operation, the chamber runs smoothly and there isn’t a particularly disadvantage condition. However, when the chamber meets the upper gate bay, the difference between the water level of the chamber with that of the sea-route should be less than 10mm. Meanwhile the condition that the water level of sea-route exceeds that of the chamber must be avoided, preventing too much water body flowing from the sea-route to chamber and the rope force exceeding the allowed value in the design range.
[1]
Zhu shihong Chen yidong,The
Report of Prototype observation Study of Yantan Vertical Ship Lift(hydrodynamic),
Journal of Yangitze River Scientific Research Institute. 2000、3.
[2]
Dai xianghe Zhang
linrang,The Report of Prototype observation Study of Yantan Vertical Ship
Lift(stress of structure、distortion and
oscillate ), Journal of Yangitze River Scientific Research Institute, 2000、2.
Fig.1
Mearsuing point arrangements on the prototype observation of Yantan Ship Lift
Fig.2 The wave of chamber when the door open (the level of chamber lower 0.lm than that of upstream)