Xiangcun Qi^a , Mo Yang^a,* , Yuwen Zhang^b

Frontiers in Heat and Mass Transfer, Vol.8, pp. 1-8, 2017, DOI:10.5098/hmt.8.3

Abstract The formation of thermal NO and fuel type NO emission under the air staged combustion in a tower pulverized coal fired boiler that burners are arranged in the front and the rear wall are investigated in this paper. Effects of the distribution of oxygen in the main combustion zone on NO_X are then analyze qualitatively. The results show that when the SOFA ratio is 34.98%, NO_X yield is at the minimum; thermal NO is not only related to temperature, but also by the influence of oxygen distribution. When oxygen is more and the temperature is high, it is conducive to… More >

Yuantao Liu¹, Yanzhe Li^1,*, Shanpeng Zhao^1,2, Youpeng Zhang¹, Taizhen Zhang³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2533-2547, 2023, DOI:10.32604/fdmp.2023.027471

Abstract Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena, namely, the highamplitude, low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensuing effect that wind can have on these. In this work, the galloping time history of a wire with distorted (fixed in time) shape due to the formation of ice is analyzed numerically in the frame of a fluid-solid coupling method for different wind speeds and levels of turbulence. The results show that the turbulence intensity has a moderate effect on the increase of the conductor’s aerodynamic lift… More > Graphic Abstract

Amer A. Abdulrahman¹, Bashar J. Kadhim¹, Zainab Y. Shnain¹, Hassan Sh. Majidi², Asawer A. Alwaiti^1,*, Farooq Al-Sheikh¹, Adnan A. AbdulRazak¹, Mohammed Shorbaz¹, Mazin J. Shibeeb³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2579-2595, 2023, DOI:10.32604/fdmp.2023.027454

Abstract The well-known frictional effect related to liquid-liquid two-phase flow in pipelines can be reduced using drag-reducing additives. In this study, such an effect has been investigated experimentally using a mixture of oil and water. Moreover, numerical simulations have been carried out using the COMSOL simulation software. The measurements were taken in a horizontal pipe with the length and diameter equal to 3 and 0.125 m, respectively. Moreover, Polyethylene oxide with 150 ppm was exploited to reduce the drag effect while considering different water-to-oil fractions (0.3, 0.4, 0.5, and 0.7) and a constant total flow velocity of 2.3 m/s. As made… More >

Luay Hashem Abbud^a,b,*, Hyder H. Balla^c, Ammar F. Abdulwahid^d , Zaid Sttar Karim^d

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.30

Abstract This project aims at determining both numerical and experimental to some thermal properties and its thermal expansion coefficient, thermal conductivity and mechanical properties of reinforcement of fiber glass woven with matrix of multi wall carbon nanotube MWCNT / epoxy composite. First, this powder is known to have a very good thermal properties. So, the nanopartical combined with resin has poor thermal properties. Secondly, the development a complete solution for the manufacturing of multi wall carbon nanotube /epoxy composites different volume fraction from 1% to 10% with increment of 2% to compare the result of finite element method by using ANSYS… More >

Siti Nurul Akmal Yusof^a , Yutaka Asako^a,*,Mohammad Faghri^b , Lit Ken Tan^a , Nor Azwadi bin Che Sidik^a, Wan Mohd Arif bin Aziz Japar^a

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-5, 2019, DOI:10.5098/hmt.13.25

Abstract A numerical analysis for the effect of a cylinder diameter on the state quantities for the irreversible process in a piston-cylinder system was conducted using the LB1S model. The numerical method is based on the ALE method. The cylinder-diameter range of D=0.01 m to 0.10 m was chosen. The effect of the cylinder-diameter on the state quantities was slight in the single compression with the piston velocity of -10 m/s. The ratio of the average pressure to the pressure of the reversible process at the end of the first cycle ranged from 1.00023 to 1.00462 in the cyclic compression-expansion processes… More >

Quanfu Gao^a,b , Kun Zhang^a,b,*, Liang Bi Wang^a,b

Frontiers in Heat and Mass Transfer, Vol.14, pp. 1-10, 2020, DOI:10.5098/hmt.14.29

Abstract Detailed numerical analysis is presented for natural convection heat transfer in internally finned horizontal annuli. Governing equations are discretized using the finite volume method, and solved using SIMPLE algorithm with Quick scheme. The results show that the flow and heat transfer can reach steady state when the Rayleigh number is below 2×10⁴. When the Rayleigh number is greater than 3×10⁴ , two different types of numerical solutions under the same parameters can be obtained for different initial conditions. The critical Rayleigh numbers with two different initial conditions are different from steady to unsteady solutions. The oscillatory flow undergoes several bifurcations… More >

Mahmud H. Ali^a,* , Rawand E. Jalal^a

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-14, 2020, DOI:10.5098/hmt.15.27

Abstract In this work, natural convection in an adiabatic enclosure with openings induced by two isothermal hot cylinders is approached numerically. The study covers five different configurations of the enclosure as the number and locations of the inlet and outlet ports are varied for Rayleigh number (Ra) between 10⁴ and 10⁶ . Additionally, the study also analyzes the effects of varying the horizontal distance (S) between the cylinders along with their vertical locations () for dimensionless values of 0.4 to 0.3 and -0.2 to 0.2, respectively, at a constant Ra of 10⁶ . The outcomes show that the locations of the… More >

Hongfei Cao^1,2, Zhongda Lyu^1,2,3,*, Xi Peng^2,3, Zhuo Zhao^2,3

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.9, pp. 2361-2384, 2023, DOI:10.32604/fdmp.2023.027470

Abstract In recent years, Remotely Operated Vehicles (ROVs) have played an increasingly important role in the construction and monitoring of underwater pile foundations. However, due to the open frame structure of such vehicles, a gap of knowledge still exists with regard to their hydrodynamic behavior. In this study, the hydrodynamic stability of such vehicles is investigated numerically by means of a multiple reference frame method. The hydrodynamic characteristics of the ROV when it moves horizontally and upward in the vertical plane are examined. It is found that there is interference between the horizontal and vertical thrusters of the ROV. There is… More >

Roshan Devidas Bhagat^a,*, Samir J. Deshmukh^b

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-16, 2021, DOI:10.5098/hmt.16.23

Abstract Numerical analysis of passive two phase fluid flow in a 3D Closed Loop Pulsating Heat Pipe (CLPHP) with turns in evaporator and condenser section is carried out. Water is used as working fluid. The volume of fluid model (VOF) is used to simulate passive two-phase fluid flow in a Closed Loop Pulsating Heat Pipe. Filling ratio (FR) of is kept in the range of 60 to 70%. The evaporator temperature is set in the range of 353 K. The condenser temperature is set in the range of 298 K. The contours of volume fraction water, wall temperature and contours of… More >

Yasushi Koito^a,*

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-7, 2021, DOI:10.5098/hmt.16.1

Abstract For ultra-thin heat pipes, a centered wick structure is often used. In this study, a numerical analysis is performed on an ultra-thin heat pipe in which the wick structure’s position has deviated from the center. A 3D heat pipe model, developed by the author in a previous study, is extended, and numerical calculations are conducted to determine any differences in performance because of an off-center wick. The major findings are as follows: (1) a completely centered wick structure is recommended for optimum performance; (2) accurate central positioning of the wick structure is important in the fabrication process of ultra-thin heat… More >