• Clean Technology
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• v.2 no.2
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• pp.165-175
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• 1996

Cutting fluids in machining process are one of the parameters which have serious effects on the environment. A simple method to accomplish the environmentally clean process is to evaluate the effects of cutting fluids and select one which has the least environmental load. In this research, a process planning to select the best cutting fluid is suggested considering both machinability and environmental effects. The selection criteria and evaluation method named AHP are introduced. The planning process is illustrated with drilling characterized as a heavy-duty and low-speed process. Five standard fluids are compared with respect to five environmental attributes. Compounded cutting oils are superior to water-soluble oils in both machinability and environmental effects.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.4
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• pp.370-376
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• 2006

The paper concerns an experimental study of fully developed laminar flow of a Newtonian and non-Newtonian liquid in concentric annuli with combined bulk axial flow and inner cylinder rotation. Pressure losses and skin friction coefficients have been measured for Newtonian fluid, water and non-Newtonian fluids, 0.2% aqueous of sodium carboxymethyl cellulose (CMC) and 5% bentonite solutions, when the inner cylinder rotates at the speed of $0{\sim}500$ rpm. The influences of rotation, radius ratio and working fluid on the annular flow field are investigated. And the new correlations among the skin friction coefficient, the Reynolds number and the Rossby number are presented with reasonable limits of accuracy in laminar flow regime.

• 한국전산유체공학회:학술대회논문집
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• 2003.08a
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• pp.225-230
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• 2003

The moonpool is a vertical well ill floating barge, frequently found in drilling ships and in diving support vessel. In this paper, numerical simulation of two-dimensional flow in moonpool situated in moving vessel is carried out using the commercial software FLUENT. The focus of the simulation is to understand drag generation mechanics of moonpool flow. To examine the effect of free surface motion on the drag, simulations are also carried out by employing two different boundary conditions at the free surface.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.3
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• pp.155-170
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• 2010

Availability of economic and efficient energy resources is crucial to a nation's development. Because of their low cost and advancement in drilling and exploration technologies, oil and gas based energy systems are the most widely used energy source throughout the world. The inexpensive oil and gas based energy systems are used for everything, i.e., from transportation of goods and people to the harvesting of crops for food. As the energy demand continues to rise, there is strong need for inexpensive energy solutions. An offshore platform is a large structure that is used to house workers and machinery needed to drill wells in the ocean bed, extract oil and/or natural gas, process the produced fluids, and ship or pipe them to shore. Depending on the circumstances, the offshore platform can be fixed (to the ocean floor) or can consist of an artificial island or can float. Semi-submersibles are used for various purposes in offshore and marine engineering, e.g. crane vessels, drilling vessels, tourist vessels, production platforms and accommodation facilities, etc. The challenges of deepwater drilling have further motivated the researchers to design optimum choices for semi-submersibles for a chosen operating depth. In our series of eight papers, we discuss the design and production aspects of all the types of offshore platforms. In the present part I, we present an introduction and critical analysis of semi-submersibles.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2720-2724
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• 2007

Field measurements have revealed that the pressure drop over a borehole during drilling of a slim oil well or a well with a long reach can depend significantly on the rotation speed of the drill pipe. An accurate prediction of the annular frictional pressure drop is therefore important for conditions where the annular clearance is small. An experimental study was carried out to study solid-liquid two phase flow in a slim hole annulus. Annular velocities of carrier fluids varied from 0.2 m/s to 1.5 m/s. The carrier fluids which were utilized included tap water and CMC water solutions. Pressure drops and average flow rates were measured for the parameters such as inner-pipe rotary speed, carrier fluid velocity, hole inclination and particle injection rate. For both water and CMC solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.737-744
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• 2021

An investigation is conducted to study a solid-liquid mixture vertically upward hydraulic transport of solid particles by non-Newtonian fluids in the Mud system. Rheology of particulate suspensions in viscoelastic fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study a clear acrylic pipe was used in order to observe the movement of solid particles. Annular velocities varied from 0.4 m/s to 1.2 m/s. The mud systems which were utilized included aqueous solution of sodium carboxymethyl cellulose (CMC) solutions. Main parameters considered in the study were inner-pipe rotary speed, fluid flow regime and particle injection rate. Solid volumetric concentration and pressure drops were measured for the various parameters such as inclination angle, flow rate, and rotational speed of inner cylinder.

• Economic and Environmental Geology
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• v.18 no.2
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• pp.93-105
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• 1985

Whether a skarn deposit in carbonate host occurs in contact with certain igneous mass or not has been a general criterion in identifying the igneous rock that genetically relates to the skarn deposit. It is well known, however, that there are many skarn deposits which are not close to any given igneous contact but are far away from the contact. In this paper the reason why such deposits can be formed at a distance from the contact as mentioned is expressed based on the concept that skarn deposits and related igneous rocks are genetically connected at depth where ore-forming fluids emanate from magma and are removed upwards; the movement of ore-forming fluids separated from magma at any depth may have a tendency to infiltrate upward in bulk rather than to diffuse laterally; the paths of magma and cogenetic ore-forming fluids may be identical at lower depths but the latter can be diverted from the former with upward movement so that the positions of the skarn deposits which resulted from the ore-forming fludis at upper levels can be distant from the igneous contacts on a given horizontal section. Statistics indicate that the majority of exoskarns are found at distances up to 800 meters or rarely up to 3,000 meters from igneous contacts and endoskarns up to 600 meters or more. Numerous case studies of skarn deposits in various parts of the world support the above reasoning indicating a general downward convergency of skarn orebodies and related igneous masses with depth. A typical example of this situation is well demonstrated at the Keumseong molybdenum deposit, which is apart from the Jecheon granite on the surface but gets closer to the granite body with depth and finally is intertongued with the granite apophyses in its root zone. Another case for skarn deposit not associated with igneous contact either laterally or vertically but with a deep-seated distal igneous mass is the Sangdong scheelite deposit; 700 meters below the scheelite orebody a blind pluton of muscovite granite, which intruded into the Precambrian crystalline schist, has been recently discovered by deep drilling.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.517-524
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• 2014

Two key technologies of horizontal drilling and hydraulic fracturing are recognized to achieve the rapid growth of shale gas production, in specific, in the United States during last decade. The claims between environmentalists and oil companies have been debating in terms of water contamination. Nowadays, voluntary publication of chemicals from shale gas players are available in the website, FracFocus. This paper introduces chemicals that are currently used in hydraulic fracturing process. Among chemicals, guar gum and guar derivatives are dominantly consumed to increase the viscosity of hydrofracking fluids. The role of additional additives, such as breakers and biocides, is presented by explaining how they cut down the molecular structure of guar gum and guar derivatives. In addition, crosslinking agent, pH controller, friction reducer, and water soluble polymers are also presented.

• Journal of Energy Engineering
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• v.18 no.2
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• pp.87-92
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• 2009

An experimental investigation is conducted to study a 2-phase vertically upward hydraulic transport of solid particles by water and non-Newtonian fluids in a slim hole concentric annulus with rotation of the inner cylinder. Rheology of particulate suspensions in viscoelastic fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study, a clear acrylic pipe was used in order to observe the movement of solid particles. Annular velocities varied from 0.3 m/s to 2.0 m/s. The mud systems included fresh water and CMC solutions. Main parameters considered in the study were inner-pipe rotation speed, fluid flow regime and particle injection rate. A particle rising velocity and pressure drop in annulus have been measured for fully developed flows of water and of aqueous solutions. For both water and 0.2% CMC solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.318-327
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• 2002

In this paper, heat transfer and pressure oscillation characteristics on oscillating capillary tube heat pipe(OCHP) according to input heat flux, mixture ratio of working fluid and inclination angle were investigated and were compared single working fluid(R-142b) with binary mixture working fluid(R-142b-Ethano1). OCHP was made to serpentine structure of loop type with 10 turns by drilling the channels of length 220mm, width 1.5mm, and depth 1.5mm on the surface of brass plate. In this study, R-l42b and R-l42b-Ethanol were used as working fluids, the charging ratio of working fluids was 40(vol.%), the input heat flux to evaporating section was changed from 0.3W/㎠ to 1.8W/㎠, and mixture ratio of working fluid was R(100%), R(95%)-E(5%), R(90%)-E(10%), and R(85%)-E(15%). From the experimental results, it was found that the effective thermal conductivity of single working fluid was better than that of binary mixture working fluid. But, in case of binary mixture working fluid, critical heat flux was higher than that of single working fluid. And, the higher the mixture ratios of working fluid, the lower heat transfer performance. In case of pressure oscillation, as the inclination angle was lower, pressure wave was more irregular. These phenomena were more serious when the working fluid was binary mixture. Besides, when mixture ratio was higher, saturated pressure was increased, more irregular wave was observed and the mean amplitude was increased. For the same input heat flux, inclination angle and charging ratio, when pressure oscillation has sinusoidal wave, mean amplitude was small, and saturated pressure was low value, the heat transfer was excellent.