Experimental Study on Critical Heat Flux in Three Pin Bundle With Wire Spacer for Boiling Water Reactor

2016 ◽  
Author(s):  
Sho Tanabe ◽  
Dan Tri Le ◽  
Masatoshi Kondo ◽  
Minoru Takahashi
Keyword(s):  
Experimental Study ◽  
Test Section ◽  
Steel Wire ◽  
Constant Mass ◽  
Flow Loop ◽  
Rod Bundle ◽  
Teflon Tube ◽  
Local Quality ◽  
The Wire ◽  
Type Water

Related to the high conversion type BWR, the experimental study on the CHF were performed with a forced convection type water flow loop. In the test section of the loop, three heater pins as a rod bundle are installed, and water flows around the heater pins in the triangular flow channel at atomospheric pressure. The ratio of distance between two heater pins and the diameter of the heater pin (i.e., P/D) was the constant as 1.18 in all the experiments. This experiment conducted at the constant mass flux of 435 kg/m2s. The wire spacers, which were made of stainless steel wire coated by Teflon tube, were wound on the heater pins. The pitches of the wire spacer wound on the surface of the heater pins were 50 mm and 100mm. The water temperature at the inlet of the test section was controlled in the range between 60 and 90 °C by the pre-heater. The parameters in the current work were the pitch of the wire spacer and the quality at the location of the burnout (i.e., local quality). The results indicated that the CHF obtained in the test section with the wire spacer was larger than that without the wire spacer. The wire spacer must promote the CHF value. The smaller pitch of the wire spacer resulted to the smaller CHF value.

Experimental Study of Flow Critical Heat Flux in Low Concentration Water-Based Nanofluids

2008 ◽  
Author(s):  
Sung Joong Kim ◽  
Tom McKrell ◽  
Jacopo Buongiorno ◽  
Lin-Wen Hu
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Test Section ◽  
Flow Boiling ◽  
Saturation Temperature ◽  
Outlet Temperature ◽  
Flow Loop ◽  
Maximum Heat ◽  
Low Concentration

Nanofluids are known as dispersions of nano-scale particles in solvents. Recent reviews of pool boiling experiments using nanofluids have shown that they have greatly enhanced critical heat flux (CHF). In many practical heat transfer applications, however, it is flow boiling that is of particular importance. Therefore, an experimental study was performed to verify whether or not a nanofluid can indeed enhance the CHF in the flow boiling condition. The nanofluid used in this work was a dispersion of aluminum oxide particles in water at very low concentration (≤0.1 v%). CHF was measured in a flow loop with a stainless steel grade 316 tubular test section of 5.54 mm inner diameter and 100 mm long. The test section was designed to provide a maximum heat flux of about 9.0 MW/m2, delivered by two direct current power supplies connected in parallel. More than 40 tests were conducted at three different mass fluxes of 1,500, 2,000, and 2,500 kg/m2sec while the fluid outlet temperature was limited not to exceed the saturation temperature at 0.1 MPa. The experimental results show that the CHF could be enhanced by as much as 45%. Additionally, surface inspection using Scanning Electron Microscopy reveals that the surface morphology of the test heater has been altered during the nanofluid boiling, which, in turn, provides valuable clues for explaining the CHF enhancement.

Experimental Study of Hydraulics and Cuttings Transport in Circular and Non-Circular Wellbores

2013 ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus ◽  
Pål Skalle
Keyword(s):  
Experimental Study ◽  
Test Section ◽  
Drilling Fluid ◽  
Test Results ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Custom Made ◽  
Experimental Laboratory ◽  
Drilling Operations

Cuttings transport is one of the most important aspects to control during drilling operations, but the effect of wellbore geometry on hole cleaning is not fully understood. This paper presents results from experimental laboratory tests where hydraulics and hole cleaning have been investigated for two different wellbore geometries; circular and a non-circular, where spiral grooves have been deliberately added to the wellbore wall in order to improve cuttings transport. Improving hole cleaning will improve drilling efficiency in general, and will in particular enable longer reach for ERD wells. The experiments have been conducted as part of a research project where friction and hydraulics in non-circular wellbores for more efficient drilling and well construction is the aim. The experiments have been performed under realistic conditions. The flow loop includes a 12 meter long test section with 2″ diameter freely rotating drillstring inside a 4″ diameter wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal and 30° inclined positions. The test results show that borehole hydraulics and cuttings transport can be significantly improved in a non-circular wellbore relative to a circular wellbore. Investigating the cutting transport in non-circular wellbores with available models is even more complex than for circular wellbores. Most drilling models assume circular wellbores, but in reality the situation is often different. Also, it may be possible to create non-circular wellbores on purpose, as in the present study. Such a comparative, experimental study of hole cleaning in different wellbore geometries has to our knowledge previously never been performed, and the results were obtained in a custom-made and unique experimental flow loop. The results and the experimental approach could therefore be of value for any one working with drilling.

Experimental Study of Hydraulics and Cuttings Transport in Circular and Noncircular Wellbores

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Jan David Ytrehus ◽  
Pål Skalle ◽  
Arild Saasen ◽  
...  
Keyword(s):  
Experimental Study ◽  
Test Section ◽  
Drilling Fluid ◽  
Flow Loop ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Custom Made ◽  
Experimental Laboratory ◽  
Drilling Operations ◽  
Extended Reach Drilling

Cuttings transport is one of the most important aspects to control during drilling operations, but the effect of wellbore geometry on hole cleaning is not fully understood. This paper presents results from experimental laboratory tests where hydraulics and hole cleaning have been investigated for two different wellbore geometries; circular and a noncircular, where spiral grooves have been deliberately added to the wellbore wall in order to improve cuttings transport. Improving hole cleaning will improve drilling efficiency in general, and will, in particular, enable longer reach for extended reach drilling (ERD) wells. The experiments have been conducted as part of a research project, where friction and hydraulics in noncircular wellbores for more efficient drilling and well construction are the aim. The experiments have been performed under realistic conditions. The flow loop includes a 12 m long test section with 2" diameter freely rotating drillstring inside a 4" diameter wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal and 30 deg inclined positions. The test results show that borehole hydraulics and cuttings transport can be significantly improved in a noncircular wellbore relative to a circular wellbore. Investigating the cutting transport in noncircular wellbores with available models is even more complex than for circular wellbores. Most drilling models assume circular wellbores, but in reality the situation is often different. Also, it may be possible to create noncircular wellbores on purpose, as in the present study. Such a comparative, experimental study of hole cleaning in different wellbore geometries has to our knowledge previously never been performed, and the results were obtained in a custom-made and unique experimental flow loop. The results and the experimental approach could therefore be of value for any one working with drilling.

Arrangement Characteristics and Wear Distribution of Wire Rope in Parallel Grooved Multi-Layer Winding

2013 ◽  
Vol 423-426 ◽  
pp. 842-845 ◽  
Author(s):  
Zhi Hui Hu ◽  
Yong Hu ◽  
Ji Quan Hu
Keyword(s):  
Experimental Study ◽  
Wire Rope ◽  
Wire Ropes ◽  
The Wire ◽  
Wear Damage

Based on the analysis of multi-layer winding arrangement characteristic of the wire rope in Lebus drum, the experimental study is carried on wear distribution of the wire rope in parallel grooved multi-layer winding. The result shows that, the wire rope is arranged regularly in each drum area in parallel grooved multi-layer winding; the wear of wire ropes in crossover zone is more serious than that of the parallel zone; in the same-layer wire rope winding in crossover zone, the wear damage during the wire rope winding in crossover zone at the end of each-layer drum is the most serious.

Full Scale Flow Loop Experiments of Hole Cleaning Performances of Drilling Fluids

2015 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Sneha Sayindla ◽  
Bjørnar Lund ◽  
Benjamin Werner ◽  
...  
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Base Oil ◽  
Hole Cleaning ◽  
Cleaning Performance ◽  
Water Based ◽  
Fluid Properties ◽  
Drilling Cost

One important requirement for a drilling fluid is the ability to transport the cuttings out of the borehole. Improved hole cleaning is a key to solve several challenges in the drilling industry and will allow both longer wells and improved quality of well construction. It has been observed, however, that drilling fluids with similar properties according to the API standard can have significantly different behavior with respect to hole cleaning performance. The reasons for this are not fully understood. This paper presents results from flow loop laboratory tests without and with injected cuttings size particles using a base oil and a commercial oil based drilling fluid. The results demonstrate the importance of the rheological properties of the fluids for the hole cleaning performance. A thorough investigation of the viscoelastic properties of the fluids was performed with a Fann viscometer and a Paar-Physica rheometer, and was used to interpret the results from the flow loop experiments. Improved understanding of the fluid properties relevant to hole cleaning performance will help develop better models of wellbore hydraulics used in planning of well operations. Eventually this may lead to higher ROP with water based drilling fluids as obtained with oil based drilling fluids. This may ease cuttings handling in many operations and thereby significantly reduce the drilling cost using (normally) more environmentally friendly fluids. The experiments have been conducted as part of an industry-sponsored research project where understanding the hole cleaning performance of various oil and water based drilling fluids is the aim. The experiments have been performed under realistic conditions. The flow loop includes a 10 meter long test section with 2″ OD freely rotating drillstring inside a 4″ ID wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal position.

Flow Loop Investigation of Lubricant Concentration Effect on Mechanical Friction in Drilling Fluids

2016 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Knud Richard Gyland ◽  
Bjørnar Lund ◽  
Sneha Sayindla ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
North Sea ◽  
Test Section ◽  
Drilling Fluid ◽  
Drill String ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Steel Tubing ◽  
Steel Sections ◽  
Concrete Elements

A laboratory scale flow loop for drilling applications has been used for evaluating the effect of lubricants on skin friction during drilling and completion with oil based or low solids oil based fluids. The flow loop included a 10 meter long test section with 2″ OD free whirling rotating drill string inside a 4″ ID wellbore made of concrete elements positioned inside a steel tubing. A transparent part of the housing was located in the middle of the test section, separating two steel sections of equal length. The entire test section was mounted on a steel frame which can be tilted from horizontal to 30° inclination. The drilling fluids and additives in these experiments were similar to those used in specific fields in NCS. Friction coefficient was calculated from the measured torque for different flow velocities and rotational velocities and the force perpendicular to the surface caused by the buoyed weight of the string. The main objective of the article has been to quantify the effect on mechanical friction when applying different concentrations of an oil-based lubricant into an ordinary oil based drilling fluid and a low solids oil based drilling fluid used in a North Sea drilling and completion operation.

scholarly journals FRACTURE LOAD OF SILVER SOLDERED JOINTS ON STAINLESS STEEL AND COBALT-CHROMIUM ORTHODONTIC WIRES WITH VARIOUS JOINING CONFIGURATIONS

2021 ◽  
pp. 26-35
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Steel Wire ◽  
Fracture Load ◽  
Cobalt Chromium ◽  
Orthodontic Wires ◽  
Orthodontic Wire ◽  
The Wire ◽  
Site Planning ◽  
Band Material

The current research compared and analysed the tensile strength of silver soldered stainless steel and cobalt-chromium orthodontic wire joints with band material The effect of joint site planning on various orthodontic joining configurations was investigated. A total of sixty wire specimens were chosen, thirty in the stainless-steel group and thirty in the cobalt – chromium group. Again, each group's sample was divided into three subgroups, namely End – End, Round, and Orthodontic band material. The study findings suggested all three configurations can be used to make silver soldered joints regardless of the wire consistency. When subjecting the wire to joint site planning, however, stainless steel wire should be used with its limitations in mind.

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