Numerical　simulations　have　been　carried　out　to　evaluate　the　two-phase　frictional　pressure　drop　for　air-water　two-phase　flow　in　horizontal　helical　rectangular　channels　by　varying　configurations,　inlet　velocity　and　inlet　sectional　liquid　holdup.　The　investigations　performed　using　eight　coils,　five　different　inlet　velocity　and　four　different　inlet　sectional　liquid　holdups.　The　effects　of　curvature,　torsion,　fluid　velocity　and　inlet　sectional　liquid　holdup　on　two-phase　frictional　pressure　drop　have　been　illustrated.　It　is　found　that　the　two-phase　frictional　pressure　drop　relates　strongly　to　the　superficial　velocities　of　air　or　water,　and　that　the　curvature　and　torsion　have　some　effect　on　the　pressure　drop　for　higher　Reynolds　number　flows　in　large-scale　helical　rectangular　channel;　the　inlet　sectional　liquid　holdup　only　increases　the　magnitude　of　pressure　drop　in　helical　channel　and　has　no　effect　on　the　development　of　pressure　drop.　The　correlation　developed　predicts　the　two-phase　frictional　pressure　drop　in　helical　rectangular　channel　with　acceptable　statistical　accuracy.　©　2014　Elsevier　Ltd.