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

Lemu Zhou,Fangyuan Zhou,Hanbin Ge,Shuaicheng Guo

doi:10.1155/2021/5520949

Abstract

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.

Highlights

In the construction of dams and long-span suspension bridges, mass concrete blocks are cast. e released hydration heat of the massive concrete cannot be dissipated quickly because of the poor thermal conductivity of concrete. erefore, a large temperature difference can be generated between the surface and the core area of the concrete during the early stage of the pouring concrete [1,2,3]. e large temperature difference may lead to cracks, which may reduce the durability of the massive concrete [4,5,6]. erefore, reducing the internal temperature of massive concrete becomes a research hotspot during the past few decades
An efficiency way named postcooling method is often used to change the internal temperature distribution of the massive concrete structures [7, 8]. e internal temperature distribution of mass concrete can be changed by the cool water running through pipes. e cooling effect of the postcooling method has been verified during the construction process of Hoover dam in the last century [9]
Zhong et al [12] put forward a composite element method to improve the computational efficiency in the calculation of temperature distribution in mass concrete with water running in the cooling pipe. e availability of the proposed method was confirmed by finite element method. e theoretical solution of nonmetallic cooling pipe, compared with metallic cooling pipes, was investigated by Chen et al [13]

Summary

Introduction

In the construction of dams and long-span suspension bridges, mass concrete blocks are cast. e released hydration heat of the massive concrete cannot be dissipated quickly because of the poor thermal conductivity of concrete. erefore, a large temperature difference can be generated between the surface and the core area of the concrete during the early stage of the pouring concrete [1,2,3]. e large temperature difference may lead to cracks, which may reduce the durability of the massive concrete [4,5,6]. erefore, reducing the internal temperature of massive concrete becomes a research hotspot during the past few decades. E internal temperature distribution of mass concrete can be changed by the cool water running through pipes. Zhong et al [12] put forward a composite element method to improve the computational efficiency in the calculation of temperature distribution in mass concrete with water running in the cooling pipe. In terms of numerical simulation, Kim et al [15] investigated the hydration heat of the mass concrete embedded with cooling water pipeline by using a finite element program. Erefore, an annular finned cooling pipe which can increase the heat transfer area between the flowing water and its surrounding concrete is proposed in the paper to decrease the internal temperature of the concrete block. Internal temperature variation and distribution of the concrete block is calculated to study the cooling influence of the proposed annular finned cooling pipe

Description and Validation of the Numerical Model

Interior Temperature Distribution of Massive Concrete

Section D

Conclusions