Kun Zhang^a,b,* , Zhiyong Li^a,b, Jia Yao^a,b

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-8, 2022, DOI:10.5098/hmt.19.5

Abstract Detailed numerical analysis is presented for heat transfer characteristics of charging or discharging process in phase change thermal energy storage unit with inner corrugated tube. The results indicated that the charging or discharging rate of phase change material (PCM) for the case of inner corrugated tube is obviously higher than that in unit with inner plain tube due to the increasing heat transfer surface. The heat transfer rate increase with the increasing mass flow rate. However, when the mass flow rate of heat transfer fluid (HTF) is greater than 0.0315kg/s, the charge and discharge time can not be obviously shorten… More >

Qais Abid Yousif^a , Omar Rafae Alomar^a,*, Obed M. Ali^b , Omar Mohammed Ali^c

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-14, 2023, DOI:10.5098/hmt.20.20

Abstract This work involves a numerical investigation on free convection heat transfer occurred by a hot cylinder immersed in a square duct cooled from one side under different temperatures. Simulations have been done for a large ranges of Rayleigh number (10³ ≤ Ra ≤10⁷ ) and right wall temperature (0≤T_r ≤0.75). The results displayed that Nu is enhanced with rising in Ra and decreasing in T_r. The value of Nu is decreased with rising in T_r, where the maximum reduction in Nu is about 32% for T_r=0.75 as compared to T_r=0. The maximum enhancement range for Nu is found between 50%… More >

Ameer Abed Jaddoa^* , Karema Assi Hamad, Arshad Abdul Jaleil Hameed

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-9, 2023, DOI:10.5098/hmt.20.18

Abstract In the Heat Transfer process, many innovations were introduced aiming to obtain the most optimum behavior of the cooling process using nanofluids as coolant liquids. These nanofluids have gained much attention in cooling systems due to their special rheological and thermal performance. In this work, an experimental evaluation is conducted for nanofluids Al₂O₃, SiO₂, CuO, ZnO, and TiO₂ nanoparticles applied to a mini-channel. The nanofluid particles were entirely spread out in purified water (size of 15 nm) before being passed to the heat sink through a confined inflow channel. The obtained results showed that the achieved improvement rates are 25%,20%,… More >

Hussein Al-Gburi^*, Akeel Abbas Mohammed, Audai Hussein Al-Abbas

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-7, 2023, DOI:10.5098/hmt.20.17

Abstract Transferring thermal energy efficiently necessitates utilizing a heat exchanger capable of producing the full thermal power of the energy supply at lowest possible cost and time. Therefore, in the present investigation, the impact of corrugated helical coil concentric tube-in-tube heat exchanger on the thermal performance is investigated experimentally. As a continuous in our issue of heat exchanger, the corrugated helical tube-in-tube is carried out and compared with smooth helical tube-in-tube for free convection heat transfer. The set-up of the experimental apparatus are designed and utilized to be appropriate for the cooling and heating systems of working fluid. The impacts of… More >

O. M. Oyewola^a,b,* , M. O. Petinrin^a , and H. O. Sanusi^a

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-8, 2023, DOI:10.5098/hmt.20.16

Abstract The flow and heat transfer behaviour of channels with dimples and protrusions of spherical and piriform shapes was numerically explored by solving the Navier-Stokes and energy equations with a CFD software, the ANSYS Fluent 19.3, in the range of Reynolds numbers from 8,500 to 59,000. The values of the Nusselt number and friction factors were estimated and the non-dimensional Performance Evaluation Criterion (PEC) was determined to measure the thermal-hydraulic performance. The results reveal that the piriform protruded channel demonstrated a higher thermal performance with Nusselt number values of 36%, 15%, 23%, and 9% than the smooth, spherical dimpled, piriform dimpled,… More >

Linfang Fang, Fuyong Su^* , Zhen Kang, Haojun Zhu

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-9, 2023, DOI:10.5098/hmt.20.14

Abstract Taking the ladle used by a factory as an example, a three-dimensional finite element model of the ladle was established, and the temperature distribution law of the lining during the ladle transportation was studied using the finite element analysis software ANSYS, which verified the good thermal insulation performance of the nano thermal insulation layer, and analyzed and compared the temperature and distribution law of the refractory lining under the two working conditions of the heavy ladle and the empty ladle. The results show that due to the change of the boundary conditions in the empty ladle state, the temperature change… More >

Mirmanto Mirmanto^a,*, Syahrul Syahrul^a, Agung Tri Wijayanta^b

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-5, 2023, DOI:10.5098/hmt.20.9

Abstract A study to examine the effect of evaporator diameters on the performances of a custom air-water generator had been conducted in naturally room air temperatures. Performances in this study consisted of fresh water production, coefficient of performance, and total heat transfer from the air. The freshwater was attained from the dew that dropped from the evaporator walls. It was from water vapour in the air that condensed due to the low temperature of the evaporator walls. The evaporator which had dimensions of 285 mm x 12.7 mm x 480 mm was placed in an open box (top and bottom). It… More >

Ameer Abed Jaddoa^* , Hussain Saad Abd

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-12, 2023, DOI:10.5098/hmt.20.6

Abstract In this work, the demeanour of heat transfer in a cooled upstanding turbulent flow condition of supercritical carbon dioxide SC- CO2 was investigated and analyzed. Several scenarios were adopted to handle the experimental data acquired by applying a perpendicular pipe with bending tape used in the examination model. The outcomes were presented using a typical method 'the dimensionless constitution'. Also, a modification was achieved to improve the relationship among the parameters for the processes of up and down flows. The achieved results will help address this research gap on turbulent perpendicular compound heat load based on cooling conditions. Finally, the… More >

Ningbo Guo, Xianming Gao^*, Duanling Li, Jixing Zhang, Penghui Yin, Mengyi Hua

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.3, pp. 3061-3082, 2023, DOI:10.32604/cmes.2023.026657

Abstract Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths and three cross-sectional profiles was conducted. The heat transfer coefficient and bubble generation process of three microchannel structures with a width of 80 μm and a depth of 40, 60, and 80 μm were compared during the boiling process, and the factors influencing bubble generation were studied. A visual test bench was built, and test substrates of different sizes were prepared using a micro-nano laser. During the test, the behavior characteristics of the bubbles on the boiling surface and the temperature… More >

M’Barka Mourabit^1,*, Meryam Meknassi², Soukaina Fekkar¹, Soumia Mordane¹, Hicham Rouijaa³, El Alami Semma⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.7, pp. 1753-1774, 2023, DOI:10.32604/fdmp.2023.025739

Abstract

The effect of the tilt angle on mixed convection and related heat transfer in a “T” shaped double enclosure with four heated obstacles on the bottom surface is numerically investigated. The considered obstacles are constantly kept at a relatively high (fixed) temperature, while the cavity’s upper wall is cooled. The finite volume approach is used to solve the mass, momentum, and energy equations with the SIMPLEC algorithm being exploited to deal with the pressure-velocity coupling. Emphasis is put on the influence of the tilt angle on the solution symmetry, flow structure, and heat exchange through the walls. The following parameters… More > Graphic Abstract