Jiangshuai Wang^1,*, Chuchu Cai¹, Pan Fu^2,3, Jun Li^4,5, Hongwei Yang⁴, Song Deng¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.3, pp. 537-546, 2024, DOI:10.32604/fdmp.2023.030430

Abstract Multi-gradient drilling is a new offshore drilling method. The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore pressure. In this study, a new heat transfer model is proposed by which the variable mass flow is properly taken into account. Using this model, the effects of the main factors influencing the wellbore temperature are analyzed. The results indicate that at the position where the separation injection device is installed, the temperature increase of the fluid in the drill pipe is mitigated due… More >

Zhen Tian^a,*, Wenbo Jin^a, Lei Wang^b, Zhi Jin^c

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.5

Abstract Taking the axial heat conduction of wax deposition layer into account, a two-dimensional heat transfer model of calculating the temperature profile inside wax deposition layer was deduced and established based on the energy balance equation, the finite difference method was used to solve this model, and the influence of axial heat conduction on the distribution law of temperature profile inside the wax deposition layer under different boundary conditions and thickness were discussed. The results showed that: Temperature profile inside wax deposition layer in middle region of testing pipe section was mainly influenced by axial heat conduction under boundary conditions of… More >

Juanjuan Wang^*, Jiangping Nan, Yanan Wang

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.11, pp. 2761-2775, 2023, DOI:10.32604/fdmp.2023.021175

Abstract The main objective of this study is the technical optimization of a Shell-and-Tube Heat Exchanger (STHE). In order to do so, a simulation model is introduced that takes into account the related gas-phase circulation. Then, simulation verification experiments are designed in order to validate the model. The results show that the temperature field undergoes strong variations in time when an inlet wind speed of 6 m/s is considered, while the heat transfer error reaches a minimum of 5.1%. For an inlet velocity of 9 m/s, the heat transfer drops to the lowest point, while the heat transfer error reaches a… More >

Yafei Li, Yanjun Liu^*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.3, pp. 775-788, 2022, DOI:10.32604/fdmp.2022.019810

Abstract A mathematical model for one-dimensional heat transfer in pipelines undergoing freezing induced by liquid nitrogen is elaborated. The basic premise of this technology is that the content within a pipeline is frozen to form a plug or two plugs at a position upstream and downstream from a location where work a modification or a repair must be executed. Based on the variable separation method, the present model aims to solve the related coupled heat conduction and moving-boundary phase change problem. An experiment with a 219 mm long pipe, where water was taken as the plugging agent, is presented to demonstrate… More >

Jian Xie*, Cong Liang, Qingting She, Jinliang Xu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.3, pp. 157-157, 2019, DOI:10.32604/icces.2019.05222

Abstract Recently, micro/nano structured surfaces with various wettabilities have been developed to enhance condensation heat transfer. Here, two improved condensation heat transfer models were proposed to guide design of these surfaces. The first model deals with condensation on homogeneous wettability surface with nono-pillars. Compared with the classical model, the improved model behaves three features: (1) The linking from surface wettability to nano-pillars parameters is established; (2) The nano-porous thermal resistance under condensate droplets is considered; (3) The transition criteria of different droplet detachment modes including sliding, rolling and jumping is incorporated. The nano-pillars are found to have both positive and negative… More >

Ewa Majchrzak^*

Molecular & Cellular Biomechanics, Vol.10, No.3, pp. 201-232, 2013, DOI:10.3970/mcb.2013.010.201

Abstract Heat transfer processes proceeding in the living organisms are described by the different mathematical models. In particular, the typical continuous model of bioheat transfer bases on the most popular Pennes equation, but the Cattaneo-Vernotte equation and the dual phase lag equation are also used. It should be pointed out that in parallel are also examined the vascular models, and then for the large blood vessels and tissue domain the energy equations are formulated separately. In the paper the different variants of the boundary element method as a tool of numerical solution of bioheat transfer problems are discussed. For the steady… More >

A.Z. Lorbiecka¹, R.Vertnik², H.Gjerkeš¹, G. Manojlovič², B.Senčič², J. Cesar², B.Šarler^1,3

CMC-Computers, Materials & Continua, Vol.8, No.3, pp. 195-208, 2008, DOI:10.3970/cmc.2008.008.195

Abstract A numerical model is developed for the simulation of solidification grain structure formation (equiaxed to columnar and columnar to equiaxed transitions) during the continuous casting process of steel billets. The cellular automata microstructure model is combined with the macroscopic heat transfer model. The cellular automata method is based on the Nastac's definition of neighborhood, Gaussian nucleation rule, and KGT growth model. The heat transfer model is solved by the meshless technique by using local collocation with radial basis functions. The microscopic model parameters have been adjusted with respect to the experimental data for steel 51CrMoV4. Simulations have been carried out… More >