Comparison Of Ship Shaft Power Measurement And Error Analysis

The ships'high speed, high efficiency and economy have become important indicators for shipbuilding when ships evolve towards to big-size, high-speed and automation. As an important method of measuring the conversion efficiency, the measuring of shaft power has become an major parameter in newly-built ships' inspection and acceptance. Currently, the frequently-used measuring instruments of shaft power are types of vibrating-wire and resistance. This passage adopts conjoint methods of theoretical analysis and ship hoard measurement, it makes detailed analysis and summary for the theories of two methods and concrete issue in the processes of installation, debugging and actual measurement. Then, this passage analyses differences between two methods through analysis of measuring datas, it also discusses major factors which have influence on degree of accuracy and reliability. This paper mainly contains the following respects:(1) The theoretical basis of two kinds of measuring instruments are studied, The vibrating-wire shaft power meter measures based on the theory of phrase difference torque measuring, resistance shaft power meter measures based on the theory of strain torque measuring.(2) Because of the testing sensors which the two measuring systems use are much more different, this passage adopts conjoint methods of theoretical analysis and ship hoard measurement, it makes detailed analysis and summary for the theories of two methods and concrete issue in the processes of installation, debugging and actual measurement.(3) This passage analyzes the measuring datas of shaft power with Statistical methods. It founds that the accuracy of measuring data of the vibrating-wire shaft power meter is more high though analysis of discrete coefficients. This passage also compares results of the two methods when they are in the same load, it finds that the mean values which are in the same working condition and load are different, it also finds the D-value with Hypothesis testing method. In this part it also uses Single factor analysis model to analyze the influence which rotate speed gives to shaft power. (4) This passage compares and gives a test for the two series measuring datas in which are in the same round voyage under the same working condition and route, with the analysis of these data it finds out that stream and stormy waves have an influence on shaft power. Through amending these factors, it discovers that ships' performances reached at the demand of beginning design after comparing with model design.