Design criteria for low head bubbler irrigation systems

Abstract

Analysis indicates that the Blasius equation yields accurate estimates of head loss in small diameter plastic tubing and larger diameter PVC pipe for Reynolds numbers upto 100,000. The Hazen-Williams equation with suitable roughness parameter values also predicts head loss accurately. The results of laboratory experiments reveal that the undulations which are created during field installation are the primary cause of air locking in the delivery hose. The additional head needed to release the trapped air was found to be equal to the sum of heights of all the undulations. If the sum of their heights exceeds the design head loss in the delivery hose, air locking will result. The capital investment for bubbler system under study was comparable to that of a pressurized drip system. Long term savings in terms of energy and maintenance make low head bubbler systems an attractive alternative to pressurized drip systems for irrigating orchards or vineyards.