Fluid mechanics of needle valves with rounded components. Part II: Preliminary measurements

•Investigations of fluid flow inside the active space of needle valves.•Configurations involving both sharp-edged and rounded details of valve components.•Geometries of the action space.•Models and experimental set-up. In this second part of results presentation of investigations of aerodynamics of the flow in the action space of needle valves – in configurations characterised by rounding of the sensitive sharp details present in earlier investigations – there are results of pressure measurements on the action space walls. There are two sections. In the first one the attention is focused on the flows approaching from outside the entrance into the exit channel, partly blocked in various degrees by the insertion of the needle tip. The second section presents data of the pressure measured at the tip of the needle – at various lifts, various Reynolds numbers, and various configurations of the rounded and sharp part of the valve components.