Research Of Monitoring System For Ship Ballast Water System Based On LabVIEW

As the key and support to the shipbuilding industry, the ship supporting industry and its structure upgrading are crucial to the whole ship industry. At present, the ballast water is injected and discharged by estimating the ship floating state artificially. However, this kind of operation was associated with many problems such as low degree of automation, high labor intensity, harsh conditions of piping construction, low efficiency of loading and high safety risks etc. This kind of operation also restricted the structure upgrading of ship supporting industry. Therefore, it is of great significance to carry out the research on monitoring system of ship ballast water for the structure upgrading of ship supporting industry.Based on the load properties of ship’s ballast water system, analysis of parameters and type selection for the upper and lower computer hardware system were carried out, the monitoring software system of upper and lower computer was developed. Based on three kinds of ship’s ballast distribution, the properties of ship floating state calculated by using two kinds of floating state algorithm were compared and analyzed. The main research contents are as follows:Firstly, taking a VLCC equipped with the ballast water system as research object, this paper planned the work flow of the system after fully analyzed the load properties of the VLCC and functional requirements of the system. The hardware of the monitoring system was designed and the analysis of parameters and type selection for the upper and lower computer hardware system were carried out. Meanwhile, the control cabinet was also designed.Secondly, the monitoring software for the upper and lower computer was developed. The ballast system loading and discharging control software, floating state dynamic parameters calculation software, ballast system valve condition monitoring system and the alarm module software were developed based on the principle of modular design and LabVIEW system. The mathematical model of ballast calculation was established and the algorithm of moment to change trim per centimeter was applied to the ballast monitoring software, which improved the accuracy for the monitoring of ship floating state properties. Based on PLC system, the relevant control modules were designed to execute instructions of upper computer and the debug and test was carried out in the laboratory of marine engineering. The results showed that the system ran reliably and the remote data transmission and real-time monitoring of the ballast process were well realized.Finally, based on three kinds of ship ballast distribution, the properties of ship floating state calculated by using two kinds of floating algorithm were compared and analyzed. The results showed that using the algorithm of moment to change trim per centimeter to calculate the floating state properties of ballast process for large oil tankers, under small trim conditions, can increase the calculation precision. Under the automatic loading condition, automatic discharging and manual adjustment modes of a transient ship ballast condition, for fore draft at the water gauge, the algorithm of moment to change trim per centimeter reduced the error 60 mm, 60 mm and 40mm; for midship draft at water gauge, the algorithm of moment to change trim per centimeter reduced the error 14.2mm, 40 mm and 11.2mm; for after draft at water gauge, the algorithm of moment to change trim per centimeter reduced the error 60 mm, 23.6mm and 41.6mm.