scholarly journals Improving Heat Exchange Performance of Massive Concrete Using Annular Finned Cooling Pipes

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Lemu Zhou ◽  
Fangyuan Zhou ◽  
Hanbin Ge
Keyword(s):  
Concrete Block ◽  
Finite Element Models ◽  
Mass Concrete ◽  
Pipe System ◽  
Massive Concrete ◽  
Exchange Performance ◽  
Cooling Pipe ◽  
Cooling Pipes ◽  
Method Analysis ◽  
Peak Value

Cracks will be generated due to high internal temperature of the massive concrete. Postcooling method is widely employed as a standard cooling technique to decrease the temperature of the poured mass concrete. In this paper, an annular finned cooling pipe which can increase the heat transfer area between the flowing water and its surrounding concrete is proposed to enhance the cooling effect of the postcooling method. Analysis of the interior temperature variation and distribution of the concrete block cooled by the annular finned cooling pipe system and the traditional cooling pipe system was conducted through the finite element models. It is found that, for the concrete block using the proposed annular finned cooling pipe system, the peak value of the interior temperature can be further lowered. Compared with the traditional cooling pipe, the highest temperature of concrete with an annular finned cooling pipe appears earlier than that with the traditional cooling pipe.

Prevention of crack formation in massive concrete at an early age by cooling pipe system

2019 ◽  
Vol 20 (8) ◽  
pp. 1101-1107 ◽  
Author(s):  
Trong-Chuc Nguyen ◽  
Trong-Phuoc Huynh ◽  
Van-Lam Tang
Keyword(s):  
Crack Formation ◽  
Early Age ◽  
Pipe System ◽  
Massive Concrete ◽  
Cooling Pipe

scholarly journals XFEM for Thermal Crack of Massive Concrete

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Guowei Liu ◽  
Yu Hu ◽  
Qingbin Li ◽  
Zheng Zuo
Keyword(s):  
Cooling System ◽  
Concrete Structures ◽  
Thermal Cracking ◽  
Pipe System ◽  
Degree Of Hydration ◽  
Thermal Cracks ◽  
Massive Concrete ◽  
Cooling Pipe ◽  
Equivalent Equation ◽  
Viscoelastic Constitutive Model

Thermal cracking of massive concrete structures occurs as a result of stresses caused by hydration in real environment conditions. The extended finite element method that combines thermal fields and creep is used in this study to analyze the thermal cracking of massive concrete structures. The temperature field is accurately simulated through an equivalent equation of heat conduction that considers the effect of a cooling pipe system. The time-dependent creep behavior of massive concrete is determined by the viscoelastic constitutive model with Prony series. Based on the degree of hydration, we consider the main properties related to cracking evolving with time. Numerical simulations of a real massive concrete structure are conducted. Results show that the developed method is efficient for numerical calculations of thermal cracks on massive concrete. Further analyses indicate that a cooling system and appropriate heat preservation measures can efficiently prevent the occurrence of thermal cracks.

Research on the Heat Exchange Performance of Thermal Insulation Material and Cooling Pipe for Concrete Dam

2011 ◽  
Vol 291-294 ◽  
pp. 278-281
Author(s):  
Yang Zhang ◽  
Sheng Qiang
Keyword(s):  
Heat Exchange ◽  
Thermal Insulation ◽  
Concrete Block ◽  
Inversion Method ◽  
Mass Concrete ◽  
Insulation Material ◽  
Thermal Insulation Material ◽  
Cooling Pipe ◽  
Different Diameters ◽  
The Right

In the mass concrete structure construction, the thermal insulation material and cooling pipe are important temperature control materials to prevent concrete from cracking. In order to select the right materials, their heat exchange coefficients should be obtained exactly. But no proper apparatus can give the parameters through simple measure. An experiment concrete block with the dimension of 50m long and 22m wide was established near a dam construction site and the corresponding inversion calculating was applied. The experiment method is presented. The measured curves and calculated curves meet well which shows the inversed parameters reliable. Then the heat exchange coefficients of the EPE insulation materials with different thickness and the HDPE pipes with different diameters are given. The application effect shows the selected materials have achieved the goal of crack prevention. The experiment and inversion method will provide reference to other cases and the heat exchange coefficients can be used in similar structures.

Comportement thermique et mécanique du béton de masse au jeune âge

1996 ◽  
Vol 23 (6) ◽  
pp. 1199-1206
Author(s):  
N. Bouzoubaâ ◽  
M. Lachemi ◽  
P.-C. Aïtcin ◽  
B. Miao
Keyword(s):  
Numerical Models ◽  
Autogenous Shrinkage ◽  
Concrete Block ◽  
Experimental Results ◽  
Mass Concrete ◽  
Strain Gages ◽  
Concrete Element ◽  
Shrinkage Temperature ◽  
Massive Concrete ◽  
Good Agreement

The paper presents the main results obtained from experimental and numerical investigations of the thermal and mechanical behaviors observed during curing of a massive concrete element made with type 20M cement. An experimental concrete block 920 mm in diameter and 1000 mm in thickness was instrumented with thermocouples and vibrating-wire strain gages in order to monitor the early age behavior of mass concrete. A numerical model was used to predict the temperature field that occurs in the concrete element upon hydration of cement. The modeling of the mechanical behavior was achieved using a law that accounts for autogenous shrinkage. The experimental results illustrate the importance of selecting the type of cement for use in mass concrete. The data provided by the numerical models are in good agreement with the experimental results. Key words: dam, mass concrete, deformation, finite elements, thermal gradient, instrumentation, autogenous shrinkage, temperature. [Journal translation]

The Design of Cooling Water Pipe and Cooling Analysis in Mass Concrete

2011 ◽  
Vol 255-260 ◽  
pp. 3510-3513
Author(s):  
Pan Wu Li ◽  
Qian Qian Si
Keyword(s):  
Heat Transfer Performance ◽  
Cooling Water ◽  
Mass Concrete ◽  
Water Cooling ◽  
Water Pipe ◽  
External Temperature ◽  
Concrete Cracking ◽  
Massive Concrete ◽  
Water Pipe Cooling ◽  
Cooling Pipes

Inconstruction process of mass concrete is apt to form excessive temperature stress and cause mass concrete cracking, because of its high inner temperature, big internal and external temperature difference. In order to prevent their cracking, in mass concrete of the internal Settings with cooling water pipe cooling is one of the commonly used massive concrete construction method. This paper presents a massive concrete design of cooling water cooling and calculation theory, based on the cooling pipes in concrete heat transfer performance, through the cooling water pipe and concrete heat exchange principle.

Improved buried pipe element method for temperature-field calculation of mass concrete with cooling pipes

2020 ◽  
Vol 37 (8) ◽  
pp. 2619-2640
Author(s):  
Zhenyang Zhu ◽  
Yi Liu ◽  
Zhe Fan ◽  
Sheng Qiang ◽  
Zhiqiang Xie ◽  
...  
Keyword(s):  
Temperature Field ◽  
Mass Concrete ◽  
Field Calculation ◽  
Convection Coefficient ◽  
Buried Pipe ◽  
Content Type ◽  
Cooling Pipe ◽  
Calculation Results ◽  
Cooling Pipes ◽  
Element Method

Purpose The buried pipe element method can be used to calculate the temperature of mass concrete through highly efficient computing. However, in this method, temperatures along cooling pipes and the convection coefficient of the cooling pipe boundary should be improved to achieve higher accuracy. Thus, there is a need to propose a method for improvement. Design/methodology/approach According to the principle of heat balance and the temperature gradient characteristics of concrete around cooling pipes, a method to calculate the water temperature along cooling pipes using the buried pipe element method is proposed in this study. By comparing the results of a discrete algorithm and the buried pipe element method, it was discovered that the convection coefficient of the cooling pipe boundary for the buried pipe element method is only related to the thermal conductivity of concrete; therefore, it can be calculated by inverse analysis. Findings The results show that the buried pipe element method can achieve the same accuracy as the discrete method and simulate the temperature field of mass concrete with cooling pipes efficiently and accurately. Originality/value This new method can improve the calculation accuracy of the embedded element method and make the calculation results more reasonable and reliable.

scholarly journals A faster iterative method for solving temperature field of mass concrete with cooling pipes

2017 ◽  
Author(s):  
Keshi You ◽  
Feng Wang ◽  
Liujiang Wang ◽  
Zhongwei Zhao ◽  
Yun Liu
Keyword(s):  
Temperature Field ◽  
Iterative Method ◽  
Mass Concrete ◽  
Cooling Pipes

scholarly journals Modeling temperature profile in mass concrete at early ages of cement hydration

2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Ugwuanyi Donald Chidiebere ◽  
Okafor Fidelis Onyebuchi
Keyword(s):  
Ambient Temperature ◽  
Temperature Profile ◽  
Cement Hydration ◽  
Concrete Block ◽  
Control Measures ◽  
Mass Concrete ◽  
Thermally Induced ◽  
Thermal Cracks ◽  
Concrete Placement ◽  
And Control

Thermally induced cracks due to temperature gradient in mass concrete have adverse effects on its durability and service life. Heat released during the hydration of Portland cement in early age mass concrete can be quite excessive depending on the ambient temperature, cement content of the concrete mix and the size. Finite difference model using Crank Nicholson implicit method was developed based on the two dimensional unsteady state heat conduction. Optimized MATLAB based software was developed for simulation and data visualization. A mass concrete block cast with standard mix ratio and water cement ratio was used to verify the efficacy of the model. Type-K thermocouple and digital thermometer were used to monitor the temperature at time intervals. The temperature profile showed a hotter core and cooler surface except for the initial placement temperature, which exhibited a uniform temperature for all thermocouple locations. Peak temperature values were recorded within the first day of concrete placement. The model successfully predicted the temperature profile of the mass concrete at early ages of cement hydration. With the knowledge of the ambient temperature and the configuration of the mass concrete, the model can reliably predict the temperature profile from which potential for thermal cracks occurrence can be determined to enable suitable proactive preventive and control measures.  

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