Subsonic　and　sonic　steam　jet　condensation　in　subcooled　water　pipe　flow　is　investigated　experimentally　and　numerically.　Steam　plumes　are　captured　using　a　high-speed　camera,　and　thermal　hydraulic　parameters　and　heat　and　mass　transfer　are　revealed　by　a　two-fluid　model　coupled　with　a　phase　change　model.　As　the　Reynolds　number　of　water　increases,　the　steam　plumes　show　a　conical　shape　and　gradually　shorten　in　length.　The　steam　dynamic　pressure　suddenly　drops　at　the　nozzle　outlet,　and　the　water　dynamic　pressure　rises　sharply　to　the　maximum　at　the　end　of　the　two-phase　region　where　the　steam　volume　fraction　is　0.001.　Starting　from　the　single-phase　region,　the　pressure,　velocity　and　temperature　of　the　jet　are　self-similar.　The　heat　and　mass　transfer　mainly　occur　in　the　two-phase　region　with　steam　volume　fractions　between　0.01　and　0.99,　and　the　mass　transfer　reaches　the　maximum　at　the　phase　interface　with　the　steam　volume　fraction　of　0.60.　©　2022　Elsevier　Ltd