Influence of Environmental Conditions on Temperature Field of Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 1661-1666
Author(s):  
De Jian Shen ◽  
Hao Luan ◽  
De Qing Jia ◽  
Li Zhang
Keyword(s):  
Experimental Study ◽  
Temperature Field ◽  
Wind Speed ◽  
Temperature Difference ◽  
Environmental Conditions ◽  
Large Temperature ◽  
Early Age ◽  
Large Temperature Difference ◽  
Peak Value

The temperature cracking of early-aged concrete is often met by constructors in recent years, because of large temperature difference of core and surface of concrete. Experimental study on temperature field of concrete under different environmental conditions is conducted. Different environmental conditions such as wind speed, formwork removal, sun radiation and conservation are involved. The influence of environmental conditions on the peak value of rising temperature, temperature difference of core and surface and descending speed of temperature of concrete is studied. Result obtained from this study can be used in controlling of early-age cracking of concrete.

Synthesis and characterization of a quaternary copolymer retarder for cementing in a long sealing section with large temperature difference

2020 ◽  
Vol 44 (9) ◽  
pp. 3771-3776
Author(s):  
Zhigang Peng ◽  
Chen Chen ◽  
Qian Feng ◽  
Yong Zheng ◽  
Huan Liu ◽  
...  
Keyword(s):  
Temperature Difference ◽  
Synthesis And Characterization ◽  
Large Temperature ◽  
Temperature Range ◽  
Large Temperature Difference

We synthesized a retarder, which has excellent thickening performance in the temperature range of 90–150 °C.

Experimental Study of the Temperature Field Equation in the Leeward Tunnel during Mine Fire Period

2012 ◽  
Vol 588-589 ◽  
pp. 1842-1848
Author(s):  
Wen Cai Wang ◽  
Yu Hong Jiang ◽  
Tao Hou ◽  
Wei Liu ◽  
Yang Lu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Temperature Field ◽  
Field Equation ◽  
Wind Speed ◽  
Stable Phase ◽  
Measuring Point ◽  
Mine Fire ◽  
Mine Roadway ◽  
Set Up

According to the principle of heat transfer, the temperature field equation in the leeward tunnel was set up and the experimental device with a ratio of 1:20 was built. When it happened to fire in roadway, the correctness of the temperature field equation can be verified by the experiment. In experiments, the armored thermocouple and color paperless recorder were used to record the temperature of each measuring point. The S-3-300 pitot tube and YJB-2500 compensation micro-manometer were used to determine the wind speed. When the mine roadway fired, the experiment determined the temperature field equation experiment coefficient of Kc. It showed that in the developing phase of the fire Kc= 15 ~ 20, in the stable phase of the fire Kc= 10 ~ 15, in the failing phase of the fire Kc= 20 ~ 25.

302 Numerical Analysis of Natural Convection with Large Temperature Difference

2001 ◽  
Vol 2001.54 (0) ◽  
pp. 75-76
Author(s):  
Nobuyuki FUCHIMOTO ◽  
Kazuyoshi MATSUZAKI ◽  
Kazunori KOURA ◽  
Sinya WAKAMIZU ◽  
Hiroaki KURISIMA ◽  
...  
Keyword(s):  
Natural Convection ◽  
Numerical Analysis ◽  
Temperature Difference ◽  
Large Temperature ◽  
Large Temperature Difference

Synthesis and Characterization Performance of a Novel High Temperature Retarder Applied in Long Cementing Interval

2016 ◽  
Vol 847 ◽  
pp. 479-484 ◽  
Author(s):  
Ya Lu ◽  
Ming Li ◽  
Zi Han Guo ◽  
Xiao Yang Guo
Keyword(s):  
Thermal Stability ◽  
Compressive Strength ◽  
High Temperature ◽  
Temperature Difference ◽  
Ph Value ◽  
Rapid Development ◽  
Large Temperature ◽  
Gravimetric Analysis ◽  
Sedimentation Stability ◽  
Large Temperature Difference

In view of the common polymer retarder of AMPS has poor sedimentation stability for slurry in high temperature, and thickening curve for unusual problems, a new terpolymers retarder PSIH which can solve the problem for the large temperature difference was synthesized by free radical aqueous solution copolymerization using styrene sulfonate (SSS), Itaconic acid (IA) and unsaturated hydroxyl ester monomers X . The structure and thermal stability of the copolymer was characterized with gel permeation chromatography (GPC), infrared spectroscopy (IR), and thermal gravimetric analysis (TG). The application performance of the retarder was assessed. The results demonstrated as follows. 1) The preferred synthesis conditions of the retarder is: the mass ratio of SSS/IA/X=9: 3: 1, temperature=60°C, initiator concentration =2%, the reaction time=5h, pH value was controlled in the neutral bias acidity. 2) Synthetic copolymer is the target product with appropriate molecular weight and has good thermal stability with thermal decomposition temperature of the main chain up to 375°C. 3) Compared with ordinary retarder the PSIH has merits as follows: excellent thermal resistant ability and sedimentation stability in high temperature; the rapid development of compressive strength in low temperature, and a big temperature span (30 °C~150 °C). The thickening time of the slurry with 1.0% PSIH is 245 min at 150°C; the compressive strength of cement with the same dosage can get up to 4.7MPa at 30 °C. In short, PSIH has excellent ability to cope with large temperature difference, providing a strong technical support for complex deep well cementing.

Dry Cooling Towers for GT-MHR

2008 ◽  
Author(s):  
C. B. Baxi
Keyword(s):  
Temperature Difference ◽  
High Efficiency ◽  
Large Temperature ◽  
Preliminary Evaluation ◽  
Cooling Systems ◽  
Power Cost ◽  
Heat Rejection ◽  
Large Temperature Difference ◽  
Turbine Inlet ◽  
Dry Cooling

Due to problems with the availability and the price of water, and the concerns relating to adverse environmental effects of wet cooling systems, the need for water conserving cooling systems has been increasing. Presently, dry cooling accounts for over 30,000 MWe of capacity in more than 30 countries. GT-MHR is specially suited for use of dry cooling due to 1) high efficiency, 2) high heat rejection temperatures and 3) large temperature difference between the turbine inlet and heat rejection temperatures. Higher efficiency means the amount of energy rejected to the cooling per MWe is less. The majority of heat is rejected in precooler and intercooler at helium temperature of more than 100 °C. This results in higher temperature difference for heat rejection. Also due to large temperature difference between the turbine inlet and heat rejection temperatures, changes in ambient temperature have a smaller effect on overall thermal efficiency. Preliminary evaluation shows that pure dry cooling is economical for GT-MHR for water cost of more than 0.8$/m3 and power cost of 3.5 c/kWh. A combination of dry and wet cooling can reduce large percentage of the water use without affecting the efficiency.

Development of integrated two-stage thermoelectric generators for large temperature difference

2019 ◽  
Vol 62 (9) ◽  
pp. 1596-1604 ◽  
Author(s):  
Jun Pei ◽  
LiangLiang Li ◽  
DaWei Liu ◽  
BoPing Zhang ◽  
Yu Xiao ◽  
...  
Keyword(s):  
Temperature Difference ◽  
Large Temperature ◽  
Thermoelectric Generators ◽  
Two Stage ◽  
Large Temperature Difference
Sign in / Sign up

Export Citation Format

Share Document