THROTTLE CONTROL IN CLOSED IRRIGATION NETWORKS: CALCULATION OF PRESSURE INCREASE

The article presents a comparison of three methods for calculating the hydraulic shock that occurs in a pipeline system due to the closure of a valve. The analysis based on the data from the classical hydraulic reference book allowed us to identify the peculiarities of wave processes in the initial phase of the shock phenomenon. It was found that at the time of reflection of the first wave of pressure reduction, the valve is not yet completely closed, as a result of which the reverse wave reaches it before the primary wave of pressure increase is completed. This leads to a partial damping of the forward wave, as the superposition of oppositely directed oscillations reduces the pressure amplitude. Next, a new forward wave is formed, which, upon reaching the valve, is reflected again, generating another backward pressure wave. This wave interaction is cyclic and gradually dampens under the influence of hydraulic losses and damping elements, if provided in the system. The calculations performed by formulas (2) and (3) showed significant differences in the estimation of the maximum pressure. Formula (2) revealed a tendency for a gradual increase in pressure with an increase in the valve closing time. This indicates the accumulation of wave energy in the system and the gradual increase in hydraulic load due to unquenchable wave processes. Instead, the calculations based on formula (3) showed the opposite dependence - with an increase in the closing time, the intensity of the hydraulic shock decreased. This result is likely due to a more accurate accounting of hydraulic losses, which helps to stabilize the pressure in the pipeline. The results obtained indicate significant discrepancies between the calculation methods due to differences in approaches to modeling the dynamics of flows and wave phenomena in pipeline systems. Therefore, the use of numerical methods for modeling hydraulic processes is a promising direction for improving the accuracy of predicting loads due to hydraulic shock and ensuring the reliability of hydraulic systems.