Capacity(m3) 135,000 135,000 137,000

L(m) 274 274 274

B(m) 48。2 48。2 48

D(m) 26。5 26。5 26。5

Power 39,000 BHP 39,000 BHP 31,500 BHP

    Propeller        5 blades          6 blades          5 blades     

Table 6: Summary of Measurement Information for LNG Carriers

Condition Point RPM Route

*A : Subminiature, B: Galtec

Ship A Ship B

Ballast 2 62 ~ 84 Kor。~Sing。

Loaded 1 62 ~ 84 Qatar~Sing。

Ballast 6 60 ~ 84 Kor。

Loaded 6 60 ~ 84 Qatar~Sing。

Ship C Ballast 2 60 ~ 84 Kor

Measurement Results For ballast and loaded condition of ship A, the time signals at position 1 according to rpm were depicted in Fig。 17 and 18, and the harmonic components at NCR power were shown in Fig。 19 and 20, respectively。 For ballast and loaded condition of ship B, the harmonic components at NCR power were shown in Fig。 21 and。 22, respectively。 Compared with ship A, second and third harmonic components at NCR power for ship B were relatively low amplitude。 The aftbody vibrations for ship B were comparatively better than ship A due to the characteristics of higher harmonic components of propeller fluctuating pressures。

For ballast condition of ship C, the time signals at posi- tion 1 according to rpm were depicted in Fig。 23 and the harmonic component at NCR power was shown in Fig。 24, respectively。 The characteristics of propeller fluctu- ating pressures and aftbody vibrations were considera- bly good。

摘要由螺旋桨引起的船体脉动压力，一直是船舶振动的主要激励源。在这项研究中，研究人员引入 了一种新的技术，更有效地对船体压力进行测量，这样一来，就不需要使用传感器装置孔了。专家 们还在双镇流器及负载条件下，运用该种新技术测量了三艘液化天然气运输船的船体压力。测量结 果显示，在第一、第二、第三次谐波压力分量中，螺旋桨叶片频率占据主导地位，而且螺旋桨的脉 动压力也处于较为有利的位置。这项研究的结果证实，将该种新技术用于获得实际船舶的螺旋桨脉 动压力特性是非常有帮助的。

毕业论文关键词：螺旋桨脉动压力；液化天然气运输船；测量技术；载气/负载；磁性传感器

1 概述