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Propeller & Rudder/Nozzle cavitation test

  • Open water tests of a propeller in combination with rudder and/or nozzle carried out in KHRC conventional cavitation tunnel T-32.
  • The test is arranged with the rudder mounted from the side in the middle of the tunnel’s measuring section. An headbox is arranged directly in connection with the rudder blade were a 5-axis dynamometer is installed. 
  • The nozzle is mounted from the top of the measuring section with a 1-axis force sensor, for measuring the nozzle thrust, mounted as close to the nozzle as possible.
  • Propeller thrust and torque, rudder and nozzle forces are measured at a range of different advance numbers (J) and cavitation numbers (σ) by changing the shaft speed and tunnel pressure at constant water velocity.
  • Rudder and nozzle thrust, (KTN, KTR) are added to the propeller thrust (KT) to form the total system thrust (KTT) and total open water efficiency (η0T).
  • The result is presented in a diagram showing non-dimensional thrust and torque coefficients KT, KTN, KTR, KTT and KQ, as well as open water efficiencies, η0P and η0T as a function of the advance number, J for different pitch settings and cavitation numbers.