HAMAYESH MELI FANAVARI VA SANAT DARYAEI | Year:2007 | دوره:1 |Papers Count:2

LNG IS LIQUEFIED NATURAL GAS, WHICH IS THE VERY COLD LIQUID FORM OF NATURAL GAS—THE FUEL THAT’S BURNED IN GAS STOVES, HOME HEATERS, AND ELECTRIC POWER PLANTS. WHEN IT WARMS BACK UP, LNG BECOMES NATURAL GAS AGAIN. THE NATURAL GAS CANNOT BE COOLED WITHOUT LIQUEFYING. NORMALLY, WE SHIP NATURAL GAS BY PIPELINE, BUT WE CAN’T BUILD A PIPELINE FROM THE MIDDLE EAST OR AFRICA TO THE UNITED STATES, SO ENGINEERS CREATED SHIPS CAPABLE OF CARRYING THE LIQUID FORM OF NATURAL GAS. NATURAL GAS NEEDS TO BE LIQUEFIED (COOLED TO BELOW -160OC), BECAUSE WE REQUIRE THE VOLUME CAPACITY OF 600 SHIPS OF NATURAL GAS AT AMBIENT TEMPERATURE/PRESSURE TO EQUAL ONE SHIPLOAD OF LNG. THE MOST IMPORTANT IN THESE SHIPS ARE TANK TYPES AND GASES MAINTAIN WHICH IS USED IN LNG/LPG CARRIERS. IN THIS ARTICLE, AT FIRST WE INTRODUCE EXIST TANK TYPES IN LNG/LPG CARRIERS AND THEN DISCUSS ABOUT APPLICATION OF EACH TYPE.

VERTICAL PILES ARE USED IN VARIETY OF MARINE STRUCTURES BEARING VERTICAL AND LATERAL FORCES. HOWEVER INCLINED PILE IS A STRUCTURAL ELEMENT WHICH IS PARTICULARLY USED IN TO CONFRONT THE LATERAL FORCES IN MARINE ENVIRONMENT. ALTHOUGH STUDY OF WAVE FORCES ON PILES DATES BACK TO FEW DECADES AGO, HOWEVER MANY OF THESE STUDIES MAINLY FOCUSED ON WAVE INTERACTION WITH VERTICAL PILES. THESE RESULTS THEN ROUGHLY EXTEND FOR INCLINED PILES. THIS STUDY INVESTIGATES HOW THE INCLINATION OF PILE IN SEA ENVIRONMENT AFFECTS THE HYDRODYNAMIC COEFFICIENTS. A SET OF TESTS PERFORMED ON CYLINDERS WITH DIFFERENT INCLINATIONS IN A NUMERICAL WAVE TANK WITH A PISTON-TYPE WAVE MAKER USING FLOW 3D SOFTWARE. HISTORY OF APPLIED FORCES RESULTING FROM THE MODEL RUN AND ALSO MORISON EQUATION ARE USED TO EXTRACT HYDRODYNAMIC DRAG AND INERTIA COEFFICIENTS. TO SHOW THE INFLUENCE OF PILE INCLINATION ON INERTIA AND DRAG COEFFICIENTS THE RESULTS PLOTTED AGAINST THE PILE ANGLES. THE OUTCOMES SHOWED THAT THESE COEFFICIENTS ARE VERY SENSITIVE TO WAVE CHARACTERISTICS AND PILE INCLINATION.