Experimental investigation of density stratification behavior during outer surface cooling of a containment vessel with the CIGMA facility

The experimental investigation reported provides elastic stresses in the vicinity of the unreinforced intersection of a single 90° mitred bend, subjected to an in-plane bending moment. The specimen was extensively strain gauged on the outer surface. A small number of rosettes were also laid on the inside surface close to the welded intersection. The procedures used for the successful installation of the inside surface gauges are discussed. In the experiment, consideration was also given to deflections and rotations. Satisfactory comparisons with adaptive- p thin-shell finite element results were obtained in general and differences are explained in terms of the known experimental variables and finite element approximations. The nature of the stresses at such intersections is discussed and various methods of obtaining fatigue ‘hot-spot’ stresses are considered.

Download Full-text

Experimental investigation on shear properties of warp-knitted brush fabrics

Journal of Engineered Fibers and Fabrics ◽

10.1177/1558925020946450 ◽

2020 ◽

Vol 15 ◽

pp. 155892502094645

Author(s):

Yao Chu ◽

Haitao Lin ◽

Hafsa Jamshaid ◽

Qi Zhang ◽

Pibo Ma

Keyword(s):

Experimental Investigation ◽

Shear Strength ◽

Outer Surface ◽

Shear Force ◽

Shear Resistance ◽

Experimental Results ◽

Shear Properties ◽

Factors Affecting ◽

Car Seat ◽

Seat Cushions

Warp-knitted brush fabrics are composed of an outer surface formed by weaving the front and rear needle beds with spacer yarns interposed between them. Warp-knitted brush fabrics can be used as a non-slip cover for car seat cushions; the adhesion between non-slip fabric and car seat is related to the shear strength of warp-knitted brush fabrics. In this article, to study the factors affecting the shear force of warp-knitted brush fabrics, three different processing methods and four different stretching speed intervals were used to find the effects of stiffeners and action of different speed intervals on shear properties of fabrics. The experimental results show that the stiffener treatment can improve the shear resistance of the warp-knitted brush fabrics, and the effect of different speed intervals can affect the shear resistance of fabrics. These findings will have a guiding significance in the design and production of warp-knitted brush fabrics applied to fabrics such as car seat cushions, and the results can also help to study the shear properties of warp-knitted brush fabrics for wider applications.

Download Full-text

Experimental Investigation of Rewetting During Quenching of Hot Surface by Round Jet Impingement Using Al2O3–Water Nanofluids

Volume 3: Thermal-Hydraulics ◽

10.1115/icone24-60732 ◽

2016 ◽

Cited By ~ 1

Author(s):

Avadhesh K. Sharma ◽

Mayank Modak ◽

Santosh K. Sahu

Keyword(s):

Experimental Investigation ◽

Cooling System ◽

Removal Rate ◽

Pure Water ◽

Heat Removal ◽

Jet Impingement ◽

Dimensionless Number ◽

Surface Cooling ◽

Fuel Rods ◽

Hot Surface

Impinging jet surface cooling is being used in many industrial and engineering applications due to their higher heat removal rate. Jet impingement is one of the methods to cool hot surfaces, especially in textile, metal and electronic industries. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. The usual water flow within a reactor core is bottom to top, parallel to the fuel rods. When a hot surface quenched at very high temperature using a jet of cold fluid, during the quenching the initial heat transfer is limited by film boiling. The effective cooling takes place only after the surface temperature is below the leidenfrost temperature. In the present work an experimental investigation has been carried out to analyze the rewetting phenomenon of a hot vertical stainless steel foil by circular impinging jets of pure water and Al2O3–water nanofluids. The rewetting time and rewetting velocity in the form of dimensionless number (Peclet number) obtained from the thermal images obtained from infrared thermal imaging camera (A655sc, FLIR System). Experiments are performed for different Reynolds number (Re = 5000, 8000), and Al2O3–water nanofluids concentration (Φ = 0.15%, 0.6%)

Download Full-text

Experimental investigation of steam-air condensation on containment vessel

Annals of Nuclear Energy ◽

10.1016/j.anucene.2019.107030 ◽

2020 ◽

Vol 136 ◽

pp. 107030 ◽

Cited By ~ 2

Author(s):

Ronghua Chen ◽

Penghui Zhang ◽

Pan Ma ◽

Bing Tan ◽

Zhangli Wang ◽

...

Keyword(s):

Experimental Investigation ◽

Containment Vessel

Download Full-text

Surface Cooling, Winds, and Eddies over the Continental Shelf

Journal of Physical Oceanography ◽

10.1175/jpo-d-16-0196.1 ◽

2017 ◽

Vol 47 (4) ◽

pp. 879-894 ◽

Cited By ~ 5

Author(s):

K. H. Brink

Keyword(s):

Kinetic Energy ◽

Continental Shelf ◽

Cooling Rate ◽

Baroclinic Instability ◽

Eddy Kinetic Energy ◽

Density Stratification ◽

Equilibrium Density ◽

Wind Effect ◽

Surface Cooling ◽

Model Calculations

AbstractModels show that surface cooling over a sloping continental shelf should give rise to baroclinic instability and thus tend toward gravitationally stable density stratification. Less is known about how alongshore winds affect this process, so the role of surface momentum input is treated here by means of a sequence of idealized, primitive equation numerical model calculations. The effects of cooling rate, wind amplitude and direction, bottom slope, bottom friction, and rotation rate are all considered. All model runs lead to instability and an eddy field. While instability is not strongly affected by upwelling-favorable alongshore winds, wind-driven downwelling substantially reduces eddy kinetic energy, largely because the downwelling circulation plays a similar role to baroclinic instability by flattening isotherms and so reducing available potential energy. Not surprisingly, cross-shelf winds appear to have little effect. Analysis of the model runs leads to quantitative relations for the wind effect on eddy kinetic energy for the equilibrium density stratification (which increases as the cooling rate increases) and for eddy length scale.

Download Full-text

Theoretical study of the application of the outlet diffuser of a gas turbine as a steam circuit superheater of a combined gas-steam plant

Vestnik IGEU ◽

10.17588/2072-2672.2020.5.026-037 ◽

2020 ◽

pp. 26-37

Author(s):

V.A. Chernikov ◽

E.L. Kitanin ◽

E.Yu. Semakina ◽

E.E. Kitanina

Keyword(s):

Gas Turbine ◽

Outer Surface ◽

Gas Turbines ◽

Channel Model ◽

Outer Wall ◽

Low Pressure ◽

Combined Cycle ◽

Surface Cooling ◽

Turbine Cooling ◽

Gas Turbine Exhaust

Currently, thermal insulation of GTU output diffusers uses insulation of their inner surface. This is an expensive and complicated technological procedure. For gas turbines as part of CCGT, in order to reduce the cost of insulation and at the same time increase the useful power of the turbine, cooling the diffuser outer surface with a steam stream of a steam circuit can be an alternative way of internal insulation. Steam and gas parameters of a combined cycle plant with a CCGT-450T, as well as the results of experimental and computational studies of the GTU SGT5-3000E gas turbine exhaust channel model were used. The calculations of the efficiency of the surface cooling of the diffuser with the steam coming from the steam circuit were carried out using the analytical method. A scheme of a superheater located on the outer surface of the GTU outlet diffuser operating in a combined cycle is proposed. Analytic evaluation of its effectiveness showed that the surface area of the GTU diffuser of the type SGT5-3000E is sufficient to provide the necessary overheating of low-pressure steam. Installation of such a heat exchanger using the outer surface of the diffuser provides a decrease of the temperature of its outer wall from 537 to 200 оC. The study validity is confirmed by a patent for an invention. It has been established that the use of the outer surface of the GTU outlet diffuser instead of the heat exchange surface of the low pressure superheater of the utilizer boiler can be applied at CCGT unit to reduce heat and hydraulic losses in the diffuser path and in the utilizer boiler path.

Download Full-text