טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentOren Koren
SubjectWater Tank Testing of a Laboratory Two-Phase Marine Ramjet
Engine
DepartmentDepartment of Aerospace Engineering
Supervisor Professor Emeritus Gany Alon


Abstract

The research deals with investigation and characterization of a two-phase marine ramjet engine. The operating principle of this marine engine is similar to that of the aeronautical ramjet engine, using water instead of air as the main working fluid. Energy is added via introduction of compressed air in a mixing chamber instead of a combustion process in a combustion chamber. Water enters the inlet due to vessel motion, and its pressure is increased while flowing through the diffuser; then it is mixed with compressed air at the mixing chamber, creating a two-phase jet, which generates thrust. 
A propulsion system exploiting this principle can be a promising alternative to conventional water propulsion systems based on propellers or pumps, especially in the high cruise speed range over 30 knots. The marine ramjet has no moving parts in contact with the water, and the power is transmitted to the water pneumatically. This gives the propulsion unit a long life span and simple maintenance.
The objectives of this research were :

  • Development of a laboratory test rig for investigation of the marine ramjet engine.
  • Parametric investigation of the performance and behavior of the propulsion unit.

The test rig consisted of a 10-meter diameter water tank, connected to air supply, control and data acquisition systems. Marine ramjet engine models of two different geometries were used.
Performance data were acquired experimentally, running the test system at different speeds (between 5 and 13 m/s, approximately 10 to 26 knots) and different air flow rates.
Comparison between the experimental results and theoretical predictions revealed good qualitative and fair quantitative agreement.