scholarly journals Investigation of Bath/Freeze Lining Interface Temperature Based on the Rheology of the Slag

JOM ◽  
2021 ◽  
Author(s):  
Samant Nagraj ◽  
Mathias Chintinne ◽  
Muxing Guo ◽  
Bart Blanpain

AbstractFreeze lining is a solidified layer of slag formed on the inner side of a water-cooled pyrometallurgical reactor, which protects the reactor walls from thermal, physical, and chemical attacks. Because of the freeze lining's high thermal resistance, the reactor heat losses strongly depend on the freeze lining thickness. In a batch process such as slag fuming, the conditions change with time, affecting the freeze lining thickness. Determining the freeze lining thickness is challenging as it cannot be measured directly. In this study, a conceptual framework based on the morphology and microstructure of freeze lining and the rheology of the slag is discussed and experimentally evaluated to determine the freeze lining thickness. It was found that the bath/freeze lining interface lies just below critical viscosity temperature. The growth of the freeze lining is primarily controlled by the mechanical and thermal degradation of the crystals forming at the interface. The bath/freeze lining interface temperature for the measured slag lies in the range of 1035–1070°C.

2014 ◽  
Vol 132 (8) ◽  
pp. n/a-n/a ◽  
Author(s):  
Young Shin Park ◽  
Jong Wha Lee ◽  
Young Sik Nam ◽  
Won Ho Park

2018 ◽  
Vol 851 ◽  
pp. 231-244 ◽  
Author(s):  
F. G. H. Schofield ◽  
S. K. Wilson ◽  
D. Pritchard ◽  
K. Sefiane

The evaporation of sessile droplets is analysed when the influence of the thermal properties of the system is strong. We obtain asymptotic solutions for the evolution, and hence explicit expressions for the lifetimes, of droplets when the substrate has a high thermal resistance relative to the droplet and when the saturation concentration of the vapour depends strongly on temperature. In both situations we find that the lifetimes of the droplets are significantly extended relative to those when thermal effects are weak.


2018 ◽  
Vol 193 (3-4) ◽  
pp. 578-584 ◽  
Author(s):  
Xavier de la Broïse ◽  
Alain Le Coguie ◽  
Jean-Luc Sauvageot ◽  
Claude Pigot ◽  
Xavier Coppolani ◽  
...  

2019 ◽  
Vol 91 ◽  
pp. 02032 ◽  
Author(s):  
Aleksey Zhukov ◽  
Timofey Dovydenko ◽  
Sergey Kozlov ◽  
Karapet Ter-Zakaryan ◽  
Ekaterina Bobrova

The article presents the results of the implementation of promising areas of construction and construction of low-rise buildings. The problems of improving the environmental safety and financial stability of agricultural construction through the implementation of effective systems that provide energy conservation, the creation of comfortable conditions in the rooms are considered. It is noted that a factor that has been given special attention in recent years is the environmental safety of the materials used and the reduction of the negative load on the environment of systems using these materials. The article provides the rationale that the heat-efficient system should not only be based on the use of materials with low thermal conductivity, but should also suggest a reasonable minimization of the joints between the products included in the insulation sheath and between products and structures. In constructions with the use of polyethylene foam, seamless insulating sheath is formed, which has high thermal resistance. The low vapor and wind permeability and moisture conductivity of polyethylene foam makes it possible to dispense with the construction without additional vapor barrier and wind protection, which improves the performance of the casing and its durability due to the reduction in the complexity of manufacturing wall structures.


Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1860 ◽  
Author(s):  
Zahid Mehmood ◽  
Ibraheem Haneef ◽  
Syed Zeeshan Ali ◽  
Florin Udrea

Minimizing conductive heat losses in Micro-Electro-Mechanical-Systems (MEMS) thermal (hot-film) flow sensors is the key to minimize the sensors’ power consumption and maximize their sensitivity. Through a comprehensive review of literature on MEMS thermal (calorimetric, time of flight, hot-film/hot-film) flow sensors published during the last two decades, we establish that for curtailing conductive heat losses in the sensors, researchers have either used low thermal conductivity substrate materials or, as a more effective solution, created low thermal conductivity membranes under the heaters/hot-films. However, no systematic experimental study exists that investigates the effect of membrane shape, membrane size, heater/hot-film length and M e m b r a n e (size) to H e a t e r (hot-film length) Ratio (MHR) on sensors’ conductive heat losses. Therefore, in this paper we have provided experimental evidence of dependence of conductive heat losses in membrane based MEMS hot-film flow sensors on MHR by using eight MEMS hot-film flow sensors, fabricated in a 1 µm silicon-on-insulator (SOI) CMOS foundry, that are thermally isolated by square and circular membranes. Experimental results demonstrate that: (a) thermal resistance of both square and circular membrane hot-film sensors increases with increasing MHR, and (b) conduction losses in square membrane based hot-film flow sensors are lower than the sensors having circular membrane. The difference (or gain) in thermal resistance of square membrane hot-film flow sensors viz-a-viz the sensors on circular membrane, however, decreases with increasing MHR. At MHR = 2, this difference is 5.2%, which reduces to 3.0% and 2.6% at MHR = 3 and MHR = 4, respectively. The study establishes that for membrane based SOI CMOS MEMS hot-film sensors, the optimum MHR is 3.35 for square membranes and 3.30 for circular membranes, beyond which the gain in sensors’ thermal efficiency (thermal resistance) is not economical due to the associated sharp increase in the sensors’ (membrane) size, which makes sensors more expensive as well as fragile. This paper hence, provides a key guideline to MEMS researchers for designing the square and circular membranes-supported micro-machined thermal (hot-film) flow sensors that are thermally most-efficient, mechanically robust and economically viable.


2011 ◽  
Vol 117-119 ◽  
pp. 195-200 ◽  
Author(s):  
Qing Zhi Zhang ◽  
Gang Wu ◽  
Zhi Yang Pang ◽  
Jin Zeng Chen ◽  
Guang Hua Li ◽  
...  

By using the high purity Cu samples as the study objects and based on the experimental measurement results of the interface thermal resistance, the study on the relations between the interface thermal resistance, the laser modulation frequency and the phase lag under different temperatures has been carried out through the Matlab numerical simulation. It is shown that the corresponding phase lag is increasingly bigger but the interface thermal resistance is increasingly smaller while the interface temperature become higher at a certain pressure; furthermore, the study on relation between the interface thermal resistance and the temperature variation has been carried out and it may be concluded based on the analysis that the interface thermal resistance changes remarkably while the temperature scope is from 20K to 60K and the interface thermal resistance varies slightly while the temperature scope is from 60K to 120K.


1988 ◽  
Vol 41 (4) ◽  
pp. 623
Author(s):  
MJ O'Keefe ◽  
JLA Francey

An experimental study of flat-plate solar collectors using ethylene, propylenediene monomer (EPDM) absorber plates is descn"bed. In spite of the high thermal resistance of this material the performance is found to compare well with metal absorbers and to be in agreement with the Hottel-Whillier-Bliss equation. There is, however, an observed increase in the heat loss coefficient for mass flow rates below a critical value.


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