Development of Air lubrication system and verification by the full scale ship test

Abstract

In late years, a demand for the carbon dioxide discharge reduction from a ship and the reduction of the operation cost has been risen more and more. According to these backgrounds, the authors are grappling with establishment of the frictional resistance reduction technology of the ship by means of the air lubrication methods. In the present paper, we carried out confirmation of the air blow condition with a mock-up examination, examination at the wharf, and the numerical computation for investigation of the valve opening rate when air lubrication method is applied to large shallow water ship. After that, we confirmed the energy saving though sea trial test. When the ship was in a horizontal state we confirmed that air was blown uniformly from each small hole, by means of mock-up examination and full-scale examination by use of actual ship at wharf. In addition, through the wharf examination, we confirmed that air was almost uniformly distributed to each branch piping in heeling condition under adequate valve opening. The analytical result of the distribution of flow rate by use of MelTHERFY almost coincides with the estimated flow rate in the heeling condition. Therefore, this method is effective as an analytical technique. Thereafter, when we used air lubrication system at the speed trial test, we confirm an energy saving effect of 12% at the maximum, and the fuel consumption is reduced at the same time.