Measuring small internal pressures along a tube during steady flow

A tube that can accurately measure small strains and pressure profiles during flow of non-Newtonian paste explosives was designed and strain gaged. Equiangular rosette strain gages were installed along the length of a 6-mm-dia, 0.46-m-long thin-walled aluminum tube. The rosettes were oriented in the classical stress gage configuration to measure circumferential stress and hence internal pressure independent of other stresses. The tube was static calibrated on a floating-piston pressure calibrator. Steady flow calibration was accomplished by extruding a viscous Newtonian silicone oil. Inlet pressure ranged from 0.5 to 2.1 MPa (75 tp 300 psi).