Study On Hydraulic Characteristics Of Water Transport With Air Bag At The Bottom Of Lock Chamber Of Medium And Low Head Lock

With the construction and development of inland river navigation,China’s ship lock construction will usher in a climax,especially the construction of ship locks on artificial canals.However,some artificial canals have no natural water replenishment mechanism and less water,so in order to ensure effective navigation depth in the canal,the problem of water saving in the operation of shiplock is particularly prominent,so it is urgent to adopt new technology to solve the problem of water consumption of shiplock.Combined with airbag is applied to the many successful cases in water conservancy project,this paper take the balloon inflated and lock chamber irrigation combination way,in a short corridor water system as the research object,the airbag arranged at the bottom of the lock chamber inside lock chamber to infuse water will balloon inflated,thus elevating lock chamber until the water meets the demand of lock water,in order to achieve the goal of water saving.Based on this,RNG K-ε turbulence model was selected and VOF method was used to capture the free water surface of the lock chamber,and the hydraulic characteristics of water transport with airbag at the bottom of the lock chamber were studied.The main research work and results are as follows:(1)The influence of air bag uniform filling on hydraulic characteristics of water delivery in different numbers was studied,and the total filling time was compared.The results showed that the longitudinal water surface wave amplitude was the largest in single row of air bags,followed by two rows of air bags,and the longitudinal water surface wave amplitude was the smallest in four rows of air bags.According to the fluctuation of transverse water surface,the fluctuation of transverse water surface is small under different layout types.(2)When a single airbag inflating accident occurs under different numbers of airbags,from the perspective of the lock chamber longitudinal dimension,the longitudinal water surface drop and fluctuation have no significant difference because the lock chamber longitudinal dimension is large and only a single airbag inflating accident occurs.From the horizontal,vertical single balloon in a single balloon inflatable accident lateral undulation has no obvious ups and downs,vertical two columns and four columns balloon accident place has a big ups and downs,lateral undulation and two columns of airbag single balloon inflated accidents in transverse gradient value is greater than four columns balloon accident transverse slope value.(3)By comparing the inflating process under different arrangement types of air bags,under the condition that the top of the air bag in the gate chamber rises at the same rate,the water volume in the gate chamber remains unchanged with the complete closure of the water delivery valve,so the water flow velocity in the gate chamber increases gradually with the top of the air bag rising.Moreover,the water body in the middle of the sluice chamber has obvious extrusion and shearing phenomenon,and the water split in the sluice chamber leads to the opposite direction of water flow on the upper and lower sides of the sluice chamber,which is obviously different from the conventional centralized water transport system lock.(4)In the arrangement of multi-row airbags,the number of airbags is more than that of single-row airbags,and there are more gaps between airbags in the gate chamber,so the extrusion and shearing phenomenon of water body in the middle of the gate chamber is more obvious.When a single airbag inflates in an accident,the flow field characteristics at the accident place are more chaotic than those at the normal inflating area.Especially when the inflating accident is near the bottom of the brake,the flow direction is significantly different from other areas,and the flow velocity at the accident place is slightly smaller than that at the top of the airbag where the gas bag normally rises.