The　CFD　simulations　are　carried　out　for　the　flows　in　a　horizontally　oriented　helical　pipe　with　various　inlet　sectional　liquid　holdups　and　coil　pitches　(H).　The　development　of　the　pressure　fields　for　the　single　phase　air　flow　and　the　air-water　two-phase　flow　through　the　helical　rectangular　channels　is　studied.　The　points　with　a　higher　pressure　often　become　the　position　of　expansion　leakage.　The　liquid　phase　distribution　at　these　points　can　prevent　the　leakage　of　air.　It　is　shown　that　the　increase　of　the　inlet　sectional　liquid　holdup　may　increase　the　local　liquid　holdup　at　the　outmost　side　of　the　helical　channel.　Based　on　the　published　pressure　drop　correlation,　a　new　modified　relation　for　predicting　the　pressure　drop　in　the　helical　rectangle　channel　is　proposed.