scholarly journals A Model for Intact and Damage Stability Evaluation of CNG Ships during the Concept Design Stage

2019 ◽  
Vol 7 (12) ◽  
pp. 450 ◽  
Author(s):  
Francesco Mauro ◽  
Luca Braidotti ◽  
Giorgio Trincas
Keyword(s):  
Natural Gas ◽  
Design Process ◽  
Design Stage ◽  
Concept Design ◽  
Compressed Natural Gas ◽  
Hull Form ◽  
Intact Stability ◽  
Damage Stability ◽  
Marine Engineering ◽  
Feasible Solutions

To face the design of a new ship concept, the evaluation of multiple feasible solutions concerning several aspects of naval architecture and marine engineering is necessary. Compressed natural gas technologies are in continuous development; therefore, there are no available databases for existing ships to use as a basis for the design process of a new unit. In this sense, the adoption of a modern multi-attribute decision-based method can help the designer for the study of a completely new ship prototype. A database of compressed natural gas ships was generated starting from a baseline hull, varying six hull-form parameters by means of the design of experiment technique. Between the attributes involved in the concept design process, stability is for sure one of the most relevant topics, both for intact and damaged cases. This work describes two approaches to identify the compliance of a ship with the intact stability regulations based on the ship main geometrical quantities. Moreover, a metamodel based on the maximum floodable length concept (damage stability) allows determining the main internal subdivision of the ship. The metamodel outcomes were compared with results from direct calculations on a ship external to the database, highlighting the adequate accuracy given by the developed methods.

DEEPWATER GAS FIELD PRODUCTION FROM SUBSEA WELLS INTO COMPRESSED NATURAL GAS CARRIERS THROUGH A HYBRID RISER TOWER

2005 ◽  
Vol 45 (1) ◽  
pp. 45
Author(s):  
J-F. Saint-Marcoux ◽  
C. White ◽  
G.O. Hovde
Keyword(s):  
Natural Gas ◽  
Eddy Currents ◽  
Gas Production ◽  
Lessons Learned ◽  
Concept Design ◽  
Vertical Load ◽  
Gas Field ◽  
Compressed Natural Gas ◽  
Field Development ◽  
Field Production

This paper addresses the feasibility of developing an ultra-deepwater gas field by producing directly from subsea wells into Compressed Natural Gas (CNG) Carrier ships. Production interruptions will be avoided as two Gas Production Storage Shuttle (GPSS) vessels storing CNG switch out roles between producing/storing via one of two Submerged Turret Production (STP) buoys and transport CNG to a remote offloading buoy. This paper considers the challenges associated with a CNG solution for an ultra-deepwater field development and the specific issues related to the risers. A Hybrid Riser Tower (HRT) concept design incorporating the lessons learned from the Girassol experience allows minimisation of the vertical load on the STP buoys. The production switchover system from one GPSS to the other is located at the top of the HRT. High-pressure flexible flowlines with buoyancy connect the flow path at the top of HRT to both STP buoys. System fabrication and installation issues, as well as specific met ocean conditions of the GOM, such as eddy currents, have been addressed. The HRT concept can be also used for tiebacks to floating LNG plants.

scholarly journals Modeling the Consequences of Methane Gas Expansion in a CNG Fuel Stations of Isfahan Province

2021 ◽  
Author(s):  
Mahdieh RASTIMEHR ◽  
Mahshid BAHRAMI ◽  
Adel MAZLOMI ◽  
Mohammad Hossein CHALAK ◽  
Reza POURBABAKI
Keyword(s):  
Natural Gas ◽  
Thermal Radiation ◽  
Design Process ◽  
Pressure Vessel ◽  
Safe Distance ◽  
Compressed Natural Gas ◽  
Isfahan Province ◽  
Vapor Cloud ◽  
Fire And Explosion ◽  
Gas Expansion

Introduction: Assessment of the consequences of hazards such as fire and explosion is one of the most urgent and important steps to improve the level of safety in the current stations and those that are in the design process. The purpose of this study was to review the model of CNG Compressed Natural Gas releases and the range of damages to individuals and equipment. Moreover, we examined the observance of safe distance of this station to its surroundings. Materials and Methods: In this study, modeling the effects of fire and explosion on the CNG fuel station in Isfahan province was performed using ALOHA software. In this model, six scenarios were designed to create a hole with a diameter of 0.03m and a gap of 0.2m and width of 0.2 m in a pressure vessel. Results: It was observed that the toxic atmosphere was within the distance of 55 meters at a concentration of 65000 ppm. In the case of a gap, the toxic vapor cloud range could increase to 66 meters. The flammable superpower range was 89meters for the hole but 107 meters for the gap. The thermal radiation from the jet fire to the distance of 25meters was 10 kw/sqm for the hole, but the thermal radiation was 10 kw/sqm for the gap to 35meters. Conclusion: The most dangerous scenario was the Jet Fire, which involved not only the CNG station, but also the municipal parking area. Furthermore,  the thermal radiation produced by the gap was greater than the hole with regard to the involved range.  

Concept Design of a New Non-Ship-Shaped FPSO

2012 ◽  
Vol 170-173 ◽  
pp. 2222-2227 ◽  
Author(s):  
Tian Ying Wang ◽  
Jian Zhang ◽  
Jin Kun Liu
Keyword(s):  
Frequency Domain ◽  
Potential Flow ◽  
Three Dimensional ◽  
Stability Margin ◽  
Hydrodynamic Performance ◽  
Concept Design ◽  
Intensive Study ◽  
Factors Affecting ◽  
Intact Stability ◽  
Damage Stability

In order to give full play to the advantages of FPSOs in the development of offshore oilfields, a new non-ship-shaped FPSO concept named IQFP is put forward through intensive study on various factors affecting the performance of FPSOs. Then, the optimized IQFP general design of a project case is presented based on the IQFP concept. The intact stability and damage stability of the IQFP are calculated and checked according to IMO rules. The hydrodynamic performance in frequency domain is simulated using the three-dimensional potential flow theory and compared with that of a ship-shaped FPSO with similar tonnage. The results indicate that the IQFP has a large stability margin and more excellent hydrodynamic performance than the ship-shaped FPSO. Through the research of this paper, the excellent characteristic of the new FPSO concept IQFP is verified and the basis and foundation are provided for the further studies.

scholarly journals LCTC Ships Concept Design in the North Europe- Mediterranean Transport Scenario Focusing on Intact Stability Issues

2021 ◽  
Vol 9 (3) ◽  
pp. 278
Author(s):  
Germano Degan ◽  
Luca Braidotti ◽  
Alberto Marinò ◽  
Vittorio Bucci
Keyword(s):  
Design Stage ◽  
Strong Impact ◽  
Large Set ◽  
Concept Design ◽  
The North ◽  
Design Alternatives ◽  
Intact Stability ◽  
Multi Attribute Decision Making ◽  
Stability Issues ◽  
The Impact

In late years, the size of RoRo cargo ships has continuously increased, leading to the so-called Large Car Truck Carriers (LCTC). The design of these vessels introduced new challenges that shall be considered during the ship design since the conceptual stage, which has a very strong impact on the technical and economic performances of the vessel during all its life-cycle. In this work, the concept design of an LCTC is presented based on Multi-Attribute Decision Making (MADM). A large set of design alternatives have been generated and compared in order to find out the most promising feasible designs. The proposed approach is based on a Mathematical Design Model (MDM) capable to assess all the main technical and economic characteristics for each design. Among the others, here focus has been done on the ship stability to assure the compliance with statutory rules within the MDM. A new stability metamodel has been developed capable to define the cross curves of stability at the concept design stage. The proposed MADM methodology has been applied to North Europe-Mediterranean transport scenario highlighting the impact of main particulars describing hull geometry on the technical and economic performances of an LCTC ship.

The Sophistication of Early Stage Design for Complex Vessels

2018 ◽  
Vol Vol 160 (SE 18) ◽  
Author(s):  
D Andrews
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Ship Design ◽  
Concept Design ◽  
Design Synthesis ◽  
Simplified Approach ◽  
Overall Design ◽  
Intact Stability ◽  
Early Stage Design ◽  
Metacentric Height

Prior to the introduction of computers into Early Stage Ship Design of complex vessels, such as naval ships, the approach to synthesising a new design had been via weight equations. When it was realised that modern naval vessels (and some sophisticated service vessels) were essentially space driven initial (numerical) sizing needed to balance weight and space, together with simple checks on resistance & powering, plus sufficient intact stability (i.e. simple metacentric height assurance). All this was quickly computerised and subsequently put on a spread-sheet to iteratively achieve weight and space balance, while meeting those simple stability and R&P checks. Thus suddenly it became possible to produce very many variants, for both trade-off of certain requirements (against initial acquisition cost) as well (apparently) optimal solutions. However as this paper argues this speeding up of a very crude synthesis approach, before rapidly proceeding into feasibility investigations of the “selected design”, has not led to a quicker overall design process, nor have new ship designs been brought earlier into service, in timeframes remotely comparable to most merchant ships. It is the argument of this paper that such a speeding up of an essentially simplified approach to design synthesis is not sensible. Firstly, there is the need to conduct a more sophisticated approach in order to proceed in a less risky manner into the main design process for such complex vessels. Secondly, further advances in computer techniques, particularly those that CAD has adopted from computer graphics advances, now enable ship concept designers to synthesise more comprehensively and thereby address from the start many more of the likely design drivers. The paper addresses the argument for a more sophisticated approach to ESSD by first expanding on the above outline, before considering important design related issues that are considered to have arisen from major R.N. warship programmes over the last half century. This has been done by highlighting those UK naval vessel designs with which the author has had a notable involvement. The next section re-iterates an assertion that the concept phase (for complex vessels) is unlike the rest of ship design with a distinctly different primary purpose. This enables the structure of a properly organised concept phase to be outlined. Following this the issue of the extent of novelty in the design of a new design option is spelt out in more detail for the seven categories already identified. The next section consists of outlining the architecturally driven approach to ship synthesis with two sets of design examples, produced by the author’s team at UCL. All this then enables a generalised concept design process for complex vessels to be outlined, before more unconventional vessels than the naval combatant are briefly considered. The concluding main section addresses how a range of new techniques might further alter the way in which ESSD is addressed, in order to provide an even better output from concept to accomplish the downstream design and build process. The paper ends with a summary of the main conclusions.

A unique application and point of truth for Naval Architecture Calculations

2015 ◽  
Author(s):  
Rodrigo Perez ◽  
Verónica Alonso
Keyword(s):  
Concept Design ◽  
Stability Criteria ◽  
Power Prediction ◽  
Naval Architecture ◽  
Complete Control ◽  
Intact Stability ◽  
Damage Stability ◽  
Cad Cam ◽  
The Stability ◽  
Definition Of

Many tools handle with the calculation of compartment definition, hydrostatics, intact and damage stability and power prediction, but these calculations are separated from the rest of ship CAD/CAM tools. Ship designers need to work closely with the shipyards, in a complex and distributed environment making necessary to have suitable tools at early design stages to ensure profitable projects. Naval architecture is handled in FORAN with a revolutionary approach, where integration and advanced features are the relevant characteristics in a single and complete set of applications that are used in conjunction to other disciplines, from concept design to operation. This new approach groups the former modules for naval architecture available in FORAN from many years, is intuitive and user-friendly. The information is stored in a database instead of a wide set of files. As regards this feature, there are two different alternatives depending on the scope of the project. If the ship designer wants to calculate only naval architecture calculations, the solutions is based on a SQLITE database suitable for a standalone application. This approach benefits a ship design office, in the study of different design alternatives very quickly but having a complete control of them. The other option is integrating the Naval Architecture with the rest of FORAN design disciplines, in a single database based in Oracle. In this case, the great benefit comes from the single truth of data from concept design to operation, which ensures dramatically the reduction of errors and re-work. After the definition of compartments in 3D, by using a very fast application, the module guides the user through the naval architecture calculations with a tree of elements very intuitive, with powerful key algorithms and with a solid representation of spaces. The definition of the necessary entities to make any kind of calculation is very fast. For the intact stability a set of standard stability criteria is provided. It is based in a quick definition of loading conditions, initial situations, flooding conditions and compartment subdivisions. And for the evaluation of the damage stability a set of standard stability criteria are also provided, following deterministic and probabilistic approaches. With these tools any naval architect is able to make very fast all the necessary studies to assure the stability regulations are complied with.

Design for Facility Over the Internet: A Case Study With Automotive Connecting Rod Designs

2001 ◽  
Author(s):  
Khurshid A. Qureshi ◽  
Kazuhiro Saitou
Keyword(s):  
Design Process ◽  
Parametric Design ◽  
Complete System ◽  
Design Stage ◽  
The Internet ◽  
Concept Design ◽  
Connecting Rod ◽  
Manufacturing Facility ◽  
Manufacturing Facilities

Abstract This paper introduces a new methodology called ‘Design for Facility over Internet (DFF)’. This methodology provides an Internet-based environment for designers to perform manufacturability analysis of product designs with respect to the capabilities of existing manufacturing facilities, upfront into the design process. In the current work, only fixturing (machining datums) capabilities of a manufacturing facility are considered. A prototype DFF system for an automotive connecting rod, is developed. The system enables the designers to design the connecting rods by considering the fixturing (datums) capabilities of existing manufacturing facilities upfront at the concept design stage. The complete system implementation will also enable the manufacturers of connecting rods to create and update the database of their capabilities over the Internet. The DFF system analyzes the parametric design with respect to the fixturing capabilities and generates suggestions for a designer, to modify his design if required, to fit the capabilities of specified facilities.

scholarly journals COMPUTER AIDED SCHEMATIC DESIGN: HOW TO MANAGE LARGE DATA IN THE EARLY STAGES OF URBAN DESIGN PROJECTS

2021 ◽  
Vol 11 (2) ◽  
pp. 52-64
Author(s):  
Tiana A. Plotnikova
Keyword(s):  
Urban Design ◽  
Design Process ◽  
Web Application ◽  
Large Scale ◽  
Design Stage ◽  
Technical Solution ◽  
Concept Design ◽  
Early Stages ◽  
Design Projects ◽  
Schematic Design

The study was designed to research and analyse the existing methods used in the industry and propose alternative solutions that would meet the growing project demand. One of the major findings of this paper shows that 65% of interviewed architects and urban designers reported a lack of data accuracy in their concept design solutions, as well as dissatisfaction with the segregated concept design process. Having identified key inefficiencies in pre-design and the schematic design stages of urban design, the study develops a multiplatform web application - a space planning tool that is capable of assisting with data informed design decisions in the early stages of large-scale urban design projects. The alternative solution allows for the execution of concept stage prototyping through UI cell modification by integrating data and generating spatial solutions based on the adjacency requirements. Purpose: the purpose of this study is to understand, improve and eliminate inefficiencies in the early stages of the urban design process. Methodology: this study will first review existing inefficiencies of the architecture and urban design industry using 2 researched methods: non-participant observations and surveys. Non-participant observations were continuous and were carried out for a period of 9 months. The group that was studied involved 17 people that worked on the early-stage design stage of large-scale architecture and urban design projects. In addition to that, a survey was carried out to examine the identified inefficiencies further and to confirm the hypothesis. The survey involved 370 industry professionals from over 15 countries. Based on the developed understanding of project delivery inefficiencies, a classification will be developed to categorize the existing software. Finally, this study will conduct a series of experiments to develop a technical solution to meet current industry demands. Results: identification of key pre-design and the schematic design inefficiencies, development of a multiplatform web application. Practical implications: the application is being tested and used in the industry of architecture, urban and spatial design, it has the potential to save companies time and financial resources.  

Product Modeling, Evaluation and Validation at the Detailed Design Stage

2011 ◽  
Author(s):  
Cristian Iorga ◽  
Alain Desrochers
Keyword(s):  
Product Development ◽  
Design Process ◽  
Design Stage ◽  
Product Modeling ◽  
Specific Product ◽  
Development Processes ◽  
Product Variation ◽  
Process Methodology ◽  
Capstone Projects ◽  
Short Time

The expansion of the markets corroborated with product customization and short time to launch the product have led to new levels of competition among product development companies. To be successful in the globalization of the markets and to enable the evaluation and validation of products, companies have to develop methodologies focused on lifecycle analysis and reduction of product variation to obtain both quality and robustness of products. Keywords: Modeling, Evaluation, Validation, Design ProcessThis paper proposes a new design process methodology that unifies theoretical results of modeling stage and empirical findings obtained from the validation stage. The evaluations and validations of engineering design are very important and they have a high influence on product performances and their functionality, as well on the customer perceptions.Given that most companies maintain the confidentiality of their product development processes and that the existing literature does not provide more detailed aspects of this field, the proposed methodology will represent a technical and logistical support intended for students or engineers involved in academic as well as industrial projects.A generic methodology will be refined based on a new approach that will take into consideration the specification types (quantitative or qualitative), the design objectives and the product types: new/improved, structural/esthetic. Hence the new generic methodology will be composed of specific product validation algorithms taking into account the above considerations. At the end of this paper, the improvements provided by the proposed methodology into the design process will be shown in the context of the engineering student capstone projects at the Université de Sherbrooke.

Upstream Stranded Raw Gas Management as Compressed Natural Gas (CNG)

2013 ◽  
Author(s):  
Michael J. Economides ◽  
Xiuli Wang ◽  
Francesco Colafemmina ◽  
Vanni Neri Tomaselli
Keyword(s):  
Natural Gas ◽  
Compressed Natural Gas
Sign in / Sign up

Export Citation Format

Share Document