Precise Simulation of Heat-Flow Coupling of Pipe Cooling in Mass Concrete

For a long time, temperature control and crack prevention of mass concrete is a difficult job in engineering. For temperature control and crack prevention, the most effective and common-used method is to embed cooling pipe in mass concrete. At present, there still exists some challenges in the precise simulation of pipe cooling in mass concrete, which is a complex heat-flow coupling problem. Numerical simulation is faced with the problem of over-simplification and inaccuracy. In this study, precise simulation of heat-flow coupling of pipe cooling in mass concrete is carried out based on finite element software COMSOL Multiphysics 5.4. Simulation results are comprehensively verified with results from theoretical solutions and equivalent algorithms, which prove the correctness and feasibility of precise simulation. Compared with an equivalent algorithm, precise simulation of pipe cooling in mass concrete can characterize the sharp temperature gradient around cooling pipe and the temperature rise of cooling water along pipeline more realistically. In addition, the cooling effects and local temperature gradient under different water flow (0.60 m3/h, 1.20 m3/h, and 1.80 m3/h) and water temperature (5 °C, 10 °C, and 15 °C) are comprehensively studied and related engineering suggestions are given.

Optimization of Thermal Management System with Water and Phase Change Material Cooling for Li-Ion Battery Pack

The cooling structure of a battery pack and coupled liquid cooling and phase change material (PCM) were designed in a thermal management system to enhance the cooling performance and extend the service life of lithium-ion battery packs. Numerical simulations were conducted based on the finite volume method. This study focuses on factors such as the layout of the terminal, flow rate of the coolant, different sections of the cooling pipe, position of the cooling pipe, and coupled liquid cooling, and investigates their influences on the operating temperature. The results show that a reasonable terminal layout can reduce heat generation inside the batteries. The appropriate flow rate and position of the cooling pipe effectively reduced the maximum temperature and minimized energy consumption. Then, the PCM was placed between the adjacent batteries near the outlet to enhance the uniformity of the battery pack. The temperature difference was reduced to near 5 K. This study provides a clear direction for improving the cooling performance and extending the service life of battery packs.

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

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.

Pengaruh Jenis Material Pipa Pendingin Terhadap Distribusi Temperatur di Dalam Beton Yang Didinginkan dengan Sistem Post Cooling

Mass concrete is a concrete casting with a large enough volume, usually used for foundations, bridges,dams and so on. The heat of hydration in the mass concrete causes a temperature difference between the inside and the outside of the concrete surface. This can cause cracks in the concrete,where the temperature inside the concrete has a higher temperature rise than the outer surface yhat is in contact with the environment. One way to control the temperature of the concrete is to use a post cooling system.Post cooling system design requires knowledge of temperatur distribution in concrete. The research was conducted by varying the cooling pipe materials used,namely steel,PVC,and PEX where the cooling water discharge and temperatur were constant.The result of the research that have been carried out show that with the same cooling water discharge and temperature,concrete with PVC cooling has a higher temperature than PEX cooling pipe or steel.

Investigation of Mechanical Strains in Thermal Compensation Loop of Superconducting NbTi Cable during Bending and Cyclic Operation

In the paper, the thermal compensation loops on a composite, superconducting NbTi cable were investigated. This type of cable is used in the superconducting, fast ramping magnets of the SIS100 synchrotron, part of the Facility for Antiproton and Ion Research (FAIR) under construction in Darmstadt, Germany. The influence of space restrictions and electromagnetic cross-talk on the design of the thermal compensation loop was discussed. Plastic deformation of cable components during bending was analyzed by numerical simulations and experiments. A three-dimensional numerical model of the cable was prepared with individual superconducting wires in contact with a central cooling pipe. The bending of a straight cable into a compensation loop shape was simulated, followed by cyclic operation of the cable during thermal cycles. The maximum strains in the superconducting strands and cooling tube were analyzed and discussed.

Experimental and Numerical Investigation of Solidification of Gallium in an Initially Emptied Horizontal Pipe Flow

In a reactor core meltdown under postulated severe accidents, the molten material (corium) could be ejected or relocated through existing vessel penetrations (cooling pipe connections), thus potentially contaminating other locations in the power plant. There exists, however, a potential for plugging of melt flow due to its complete solidification, providing the availability of an adequate heat sink. Therefore, a numerical model was created to simulate the flow of molten metal through an initially empty horizontal pipe. The numerical model was verified using a previously developed analytical model and validated against experimental tests with gallium (low melting temperature) as a substitute for corium. The numerical model was able to predict the penetration length (length of distance travelled by the molten metal) after a complete blockage occurred with an average percent error range of 9%. Since the numerical model has been verified and validated, the model can be updated to predict the penetration length in the cooling pipe in case of a severe accident.

Guided Implant Placement Using an Internally Cooling Surgical Template: A Technical Note

Cooling irrigation during implant bed preparation is mandatory to avoid overheating. Due to the surgical guide design, external cooling systems do not reach the point of entry of the implant burr. Here, a new technique for irrigation during guided implant surgery for direct rinse of the burr is described. Using computer-aided design/computer-aided manufacturing additive technology, a pin of a cooling pipe was designed and implemented in a surgical guide template. The implant bed preparation was performed while the cooling pipe was connected to the surgical guide. During surgery, the irrigation solution was directly rinsing the burr at the point of entry through the irrigation channel. The use of a cooling surgical guide seems to improve the cooling of the bone during implant bed preparation. This might lead to less thermal effect of bone cells. However, systematic studies are needed to confirm the observations of the presented case report.

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

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.