Jet-breaker dimensions effect on drop manhole energy dissipation

Drop manholes are employed to dissipate energy in steep routes of sewer and drainage systems. The jet-breaker could be used to increase energy dissipation and hydraulic performance of them under Regime R2 and studying the effects of the jet-breaker length, width, sagitta, angle, as well as the inlet pipe filling ratio on drop energy dissipation were among the aims of this research. The modern statistical Design of Experiment (DoE) methodology and dimensional analysis were utilized to design the experiments according to the 2^5 full factorial design. Seventeen jet-breakers were examined and about 350 tests were performed. The statistical analysis of the results revealed that the response variable was significantly improved when the inlet pipe filling ratio was 80% and jet-breaker sagitta was equal to zero, and its angle was at 70˚. Also, effects of jet-breaker length and width ratios were insignificant. Moreover, The use of DoE resulted in straightforward data analysis and unbiased concluding.