Numerical Study of Convection and Radiation Heat Transfer in Pipe Cable

Abstract

Pipe cable is considered as an important form for underground transmission line. The maximum electrical current (ampacity) of power cable system mostly depends on the cable conductor temperature. Therefore, accurate calculation of temperature distribution in the power cable system is quite important to extract the cable ampacity. In the present paper, the fluid flow and heat transfer characteristics in the pipe cable with alternating current were numerically studied by using commercial code COMSOL MULTIPHYSICS based on finite element method (FEM). The cable core loss and eddy current loss in the cable were coupled for the heat transfer simulation, and the difference of heat transfer performances with pure natural convection model and radiationconvection model was compared and analysed in detail. Meanwhile, for the radiation-convection model, the effects caused by radiant emissivity of cable surface and pipe inner surface, as well as the cable location in the pipe, were also discussed. Firstly, it is revealed that the radiation and natural convection heat flux on the cable surface would be of the same order of magnitude, and the radiation heat transfer on the cable surface should not be ignored. Otherwise, the cable ampacity would be underestimated. Secondly, it is found that the overall heat transfer rate on the cable surface increases as the cable surface emissivity increases, and this is more remarkable to the upper cable. While the effect caused by the radiant emissivity on the pipe inner surface would be relatively small. Furthermore, it is demonstrated that, as cable location in the pipe falls, the natural convection heat transfer would be enhanced. These results would be meaningful for the ampacity prediction and optimum design for the pipe cable.

Numerical Study of Heat Transfer and Optimum Design for Trench Laying Cables with Ceramic Plates

“…In the present study, the electromagnetic effect, heat transfer, and air flow are coupled with each other [18]. e computational domain is divided into a solid domain and fluid domain for the coupling computations.…”

“…Subsequently, the computational model and methods are validated. Since the numerical study on multiphysics coupling simulation for the trench laying cable is few, the numerical simulations for the pipe laying cable [18] are restudied. e physical model for the pipe laying cable [18] is presented in Figure 4.…”

“…Since the numerical study on multiphysics coupling simulation for the trench laying cable is few, the numerical simulations for the pipe laying cable [18] are restudied. e physical model for the pipe laying cable [18] is presented in Figure 4. ree phase cables are laid in a polyvinyl chloride (PVC) pipe.…”

“…e outer diameter of the PVC pipe is 620 mm, and the thickness of the pipe is 10 mm. e equivalent heat transfer coefficient on the outside surface of the PVC pipe (h r ) is 5 W/(m 2 •K), and the environment temperature outside the PVC pipe (T r ) is 293.15 K. Typical geometric and physical parameters for the pipe laying cable [18] are listed in Table 4.…”

Heat Transfer Analysis in a Single Spool Gas Turbine by Using Calculated-Estimated Coefficients with the Finite Element Method

“…The numerical results presented good agreement with experimental measurements. Chen-Zhao et al [9] studied the fluid flow and heat transfer characteristics in the pipe cable with alternating current by using commercial code COMSOL Multiphysics based on the finite element method. Bade et al [10] used the MATLAB/Simulink numerical model of a single cylinder, mechanical spring assisted, two-stroke natural gas fueled, spark-ignited oscillating linear engine alternator to investigate the effect of combustion and heat transfer characteristics on translator dynamics and performance.…”