Fig.B.8: Pattern of bubbly flow on ship bottom
Fig.B.9: Bubbly flow into propeller
表目次
1.1 List of ships installed with air lubrication system. . . 10
3.1 Condition of air blowing test in the cavitation tunnel. . . 27
3.2 List of baffle plate. . . 32
4.1 Principal particulars of ship. . . 56
4.2 Energy saving effect. . . 76
4.3 energy saving effect (F.O. consumption). . . 78
5.1 Positions of shear force sensors and void fraction sensors on 15 m long model. 84 5.2 Positions of shear forces sensors and void fraction sensors on round model. . . 85
5.3 15 m long model test conditions. . . 87
5.4 Round model test conditions. . . 87
6.1 Principal particulars of “Ferry NAMINOUE”. . . 99
6.2 Voyage schedule from Kagoshima to Okinawa. . . 106
6.3 Approximation coefficient of fuel oil consumption (F OC =aVp0+b). . . 112
7.1 Air lubrication system design conditions and blower speciffications. . . 116
7.2 Air lubrication system components. . . 120
A.1 Princupal particulars of tested propeller . . . 139
B.1 Experimental conditions of visualization of bubbly flow . . . 149
図目次
1.1 Relationship between EEDI reduction rate and regulation value to be attained
by ships [1]. . . 2
1.2 Bubble Injection Device (SEIUN MARU [9]). . . 6
1.3 Effect of mean bubble diameter on frictional resistance reduction [43]. . . 7
1.4 Comparison of bubble diameter and frictional resistance reduction effect [54]. 8 1.5 Comparison of frictional resistance reduction effect by Madavan et al. [26] and Kawakita et al. [42]. . . 8
1.6 ACS Demonstrator the first vessel with Air Cavity System [65]. . . 10
1.7 Large scale protptype model of the Stena Airmax [66]. . . 11
2.1 Schematic diagram of full scale ship power estimation with bubble flow drag reduction system [75]. . . 17
2.2 Definition of area covered with air bublles. . . 18
2.3 Approximation curve of skin friction coefficient [68]. . . 19
2.4 Example of energy consumption reductuin effect estimation worksheet. . . 21
3.1 Dimension of air hole. . . 26
3.2 Model of air blowing hole. . . 26
3.3 Arrangement of cavitation tunnel. . . 27
3.4 Photograph of air blowing situation. . . 29
3.5 Air blowing and diffusing situation. . . 30
3.6 Outline drawing of chamber model. . . 31
3.7 Inside of the chamber model. . . 32
3.8 Test Model of Baffle plates. . . 33
3.9 Test Model of perforated panel. . . 34
3.10 Test Model of cup. . . 34
3.11 Number of holes and Measurement position of hole. . . 35
3.12 Result of air blow test of chamber. . . 36
3.13 Sellected baffle pltaes from experiment result. . . 37
3.14 Mock-up of air chamber and recess. . . 37
3.15 Photograph of the experiment. . . 38
3.16 Air blow for mock-up model(heel angle is 0 deg). . . 38
3.17 Air blow for mock-up model(heel angle is 3 deg). . . 39
3.18 Flow diagram. . . 40
3.19 Comparison of flow rate distribution. . . 41
3.20 Analytical result of flow rate distribution (All valves are fully opened). . . 42
3.21 Analytical result of flow rate distribution (Flow rate is equally distributed under minimum valve pressure loss). . . 43
3.22 Analytical result of flow rate distribution (Heel angle is 3degrees (port side down)). . . 44
3.23 Analytical result of flow rate distribution (Valve opening is adjusted as the distribution of flow rate becomes even). . . 44
3.24 Analytical result of flow rate distribution (All valve openings are 60 deg). . . . 45
3.25 Analytical result of flow rate distribution (Valve opening are linearly varied from starboard to port). . . 46
3.26 Comparison of valve opening and flow rate (Without Heeling). . . 48
3.27 Comparison of valve opening and power of blower. . . 48
3.28 Comparison of valve opening and flow quantity (Heel angle is 1.8 degrees to-ward starboard). . . 49
3.29 Air blow of full-scale ship. . . 50
3.30 Relation between pressure loss and vale opening angle. . . 51
3.31 Analytical and measured result of flow rate distribution. . . 52
4.1 Modular carrier ship YAMATAI . . . 54
4.2 Image figure of Air Lubrication Method. . . 55
4.3 Towed vehicle for ship bottom observation. . . 57
4.4 Observation method by towed vehicle. . . 58
4.5 Observation point by towed vehicle. . . 58
4.6 Propeller observation cameras. . . 59
4.7 Shear stress sensor. . . 60
4.8 Sensor arrengement on ship bottom. . . 60
4.9 Sensor position of propeller pressure fluctuation measurements. . . 61
4.10 Sensor position of hull vibration measurements. . . 62
4.11 Air blow for full-scale ship. . . 63
4.12 Experimental result of air blow. . . 63
4.13 Observation results of ship bottom during operation (VS=abt.7kn). . . 64
4.14 Observation results of ship bottom during operation (VS=abt.7kn and 10kn). 65
4.15 Comrarison of the void fraction distribution. . . 66
4.16 Situatuin of bubble flow. . . 67
4.17 Results of propeller observation (OFF). . . 68
4.18 Results of propeller observation (ON). . . 68
4.19 Trend data shear stress and water speed (Results of ship bottom observation). 69 4.20 Results of ship bottom observation at Point 6 (Vs=9.8 kn, ON→OFF). . . . 70
4.21 Local skin friction reduction with operation. . . 71
4.22 Correlation between drag reduction and air layer thickness(NMRI)) [86]. . . . 72
4.23 Results of propeller pressure fluctuation measurements at 3.500 kW. . . 73
4.24 Results of propeller pressure fluctuation measurements at 5.000 kW. . . 73
4.25 Results of hul vibration measurements at 3500 kW. . . 75
4.26 Results of Speed Trial. . . 77
4.27 Comparison of F.O. consumption. . . 78
5.1 Photograph of the 15 m flat plate model. . . 82
5.2 Top and side views of the 15 m long model with shear force sensors and void fraction sensors. . . 82
5.3 Side views of the stern part of 15 m long model. . . 83
5.4 Photograph of the void fraction sensor. . . 83
5.5 Top, side and front views of the round model with shear force sensors and void fraction sensors. . . 85
5.6 Photograph of hull posture suppression guide. . . 86
5.7 Photographs of 15 m long model towing test at 9 m/s. . . 88
5.8 Comparison of local skin friction effect in slope angle of 5 deg model due to change in distance from air injector. . . 89
5.9 Comparison of local skin friction effect in slope angle of 10 deg model due to change in distance from air injector. . . 89
5.10 Distribution of pressure coefficientCp at port side bottom of 15 m long model by double model flow CFD. . . 90
5.11 Comparison of local void fraction distribution near wall surface in slope angle of 5 deg and 10 deg model. . . 91
5.12 Photographs of round model towing test at 9 m/s. . . 92
5.13 Streamlines near port side bottom of round model by double model CFD. . . 92
5.14 Distribution of pressure coefficient Cp at port side bottom of round model by double model flow CFD. . . 93
5.15 Comparison of local skin friction effect in round model due to change in
dis-tance from air injector. . . 93
5.16 Comparison of local void fraction distibution near wall surface at 7 m/s and 9 m/s in round model due to change in equivalent air layer thicknees. . . 94
5.17 Comparison of local void fraction distibution near wall surface at 7.5 mm equiv-alent air layer thicknees in round model due to change in towing speed. . . . 95
6.1 “Ferry NAMINOUE 8,072GT cargo-passenger ship and car ferry. . . 98
6.2 Blower for air lubrication system. . . 99
6.3 Path of ship during typical speed/power maneuver. . . 101
6.4 Comparison of ALS OFF and ON wakes. . . 101
6.5 Speed-Power curves for verification of power savings. . . 102
6.6 Propeller-induced pressure increase ratio of ALS ON to OFF. . . 103
6.7 Hull vibration increase ratio of ALS ON to OFF. . . 104
6.8 Comparison of specific fuel oil consumption. . . 105
6.9 Correlation of ship speed and BHP (Kagoshima-Naze Route). . . 107
6.10 Correlation of propller speed and BHP (Kagoshima-Naze Route). . . 107
6.11 Comparison between fuel consumption and engine output. . . 108
6.12 Comparison of mean propeller speed between F. Naminoue and F. Akebono. . 109
6.13 Correlation of propller speed and fuel oil consumption (Kagoshima-Naze Route).110 6.14 Correlation of propller speed and fuel oil consumption (Naze-Kametoku Route).110 6.15 Correlation of propller speed and fuel oil consumption (Kametoku-Wadomari Route). . . 110
6.16 Correlation of propller speed and fuel oil consumption (Wadomari-Yoron Route).111 6.17 Correlation of propller speed and fuel oil consumption (Yoron-Motobu Route). 111 6.18 Correlation of propller speed and fuel oil consumption (Motobu-Naha Route). 111 6.19 Relation between total electoric power and fuel flow rate. . . 113
7.1 Structual drawing of MTA. . . 117
7.2 Operation range of MTA. . . 117
7.3 Location of air outlets. . . 118
7.4 Example of chamber configuration. . . 119
7.5 Arrangement and shape of opening(bottom plan). . . 119
7.6 Outline arranegement of air lubrication system. . . 120
7.7 Example of installation of air lubrication system on a ferry. . . 121
7.8 Example of installation study of air lubrication system on mega container ship. 122 7.9 Example dry-dock schedule of retorofitting air lubrication system. . . 123