Support System For Schemes Generation And Decision Of Miniature LNG Carrier

As a kind of efficient clean energy, Liquid Nature Gas (LNG) has grown rapidly in recant years.The world is paying more and more attention to it. Shipping is an important way to achieve the import&export of LNG and Miniature LNG Carriers undertake the LNG transportation among large-scale coastal terminals, small-scale coastal or revierside terminals and satellite terminals.They can also be mobile bunkers to supply LNG for vessels.For historical reasons, there were little research data for Miniature LNG Carriers and few carriers in operation in the world. Miniature LNG Carriers are different from the large scale LNG Carriers not for the down-scale but for the cargo containment system in essence. As a result, new method is needed to achieve the preliminary project design of Miniature LNG Carrier with emphasis on Type-C independent cargo hold. Whether the ship form is reasonable or not has a direct influence on the technique economics of the ship. A reasonable form is important foundation of the future design.Miniature LNG Carrier with Type-C independent cargo hold is a typical kind of ship where arrangement is in the leading status. In this article, the method for schemes determination and optimal selection in the preliminary design of Miniature LNG Carrier was researched with Type-C independent cargo hold as the core. The details are as follows:1. With some Miniature LNG Carriers’information and a big amount of related ships’ information, the characteristics of the ship form were elaborated with the statistical connection between cargo volume and principal dimensions, the statistical connection among main engine power, speed and cargo volume as data support for future design;2. The characteristics of Miniature LNG Carrier’s cargo hold were summarized. The calculation of internal pressure with2-dimensional method was analyzed detailedly and a method to calculate the pressure in3-dimensional space was proposed. Then the differences and similarities between the calculation of the two kinds of methods were compared. At the same time, the influence of the associated acceleration to plating thickness calculation was analyzed. The shell plating automatic arrangement, detailed calculation of plating thickness and weight were realized;3. According to the advised cargo volume, some dimension schemes of Type-C independent cargo holds were generated and principal dimensions of the carriers, different weights, drafts and block coefficients were calculated. The reasonability of the schemes was verified through speed, stability, freeboard and dimension ratios. And the unreasonable schemes were eliminated. Some evaluation indexs were set up, the optimal scheme was chosen among the reasonable schemes with fuzzy synthesis judgement method and determined the desired scheme;4. The support system for schemes generation and decision of Miniature LNG Carrier was developed through the program design with VB.NET. The feasibility of the method was verified in this article through calculating a6000m3Miniature LNG Carrier’s schemes.