Analysing the effect of speed variation on irrigation efficiency in travelling irrigators

Abstract

Tests were carried out to analyse the affects speed variation has on irrigation efficiency in travelling irrigators. These trials required the data collection of a number of different parameters, these being longitudinal and lateral depth; applied velocity variation; water flow and pressure. From these results, distribution uniformity and velocity variations can be deduced. It was found that velocity variation reduced distribution uniformity, and the velocity variation characteristics are dependent on the drive mechanism. The auxiliary engine offered consistent average velocity with small oscillating velocity values, while the turbine's velocity tended to vary slightly more across the run. As well, oscillations were greater, while the piston drive mechanism tended to change rapidly with no particular trend. It was decided this was due to a characteristic of the drive mechanism itself, as the test data offered no other reasons for the extreme variations. It was also concluded that the cable drum radius changes significantly across the run, causing variation in speed over the whole run as possibly causing oscillations throughout. It was concluded that irrigation efficiency is influenced by the drive mechanism in use, and improvements in the performance of these drive mechanisms could be achieved if the cable could be applied evenly onto the cable drum.