Vol 8, No 3 (2025)

Table of Contents

Open Access
Article
Article ID: 9828
by Prashant B Dehankar
Therm. Sci. Eng. 2025, 8(3);    102 Views
Abstract

Heat transfer augmentation procedures, such as Heat Transfer Enhancement and Intensification, are commonly used in heat exchanger systems to enhance thermal performance by decreasing thermal resistance and increasing convective heat transfer rates. Swirl-flow devices, such as coiled tubes, twisted-tape inserts, and other geometric alterations, are commonly used to create secondary flow and improve the efficiency of heat transfer. This study aimed to explore the performance of a heat exchanger by comparing its performance with and without the use of twisted-tape inserts. The setup consisted of a copper inner tube measuring 13 mm in inner diameter and 15 mm in outer diameter, together with an outer pipe measuring 23 mm in inner diameter and 25 mm in outer diameter. Mild steel twisted tapes with dimensions of 2 mm thickness, 1.2 cm width, and twist ratios of 4.3 and 7.2 were utilised. The findings indicated that the heat transfer coefficient was 192.99 W/m²°C when twisted-tape inserts were used, while it was 276.40 W/m²°C without any inserts. The experimental results closely aligned with the theoretical assumptions, demonstrating a substantial enhancement in heat transfer performance by the utilisation of twisted-tape inserts. The study provides evidence that the utilisation of twisted-tape inserts resulted in a nearly two times increase in the heat transfer coefficient, hence demonstrating their efficacy in augmenting heat transfer.

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Open Access
Article
Article ID: 9783
by Sorin Mircea Axinte
Therm. Sci. Eng. 2025, 8(3);    91 Views
Abstract

 The last decades have offered new challenges to researchers worldwide through the problems our planet is facing both in the environment protection field and the need to replace fossil fuels with new environmentally friendly alternatives. Bioenergy as a form of renewable energy is an acceptable option from all points of view and biofuels due to their biological origin have the ability to satisfy the new needs of humanity. By releasing some non-polluting combustion products into the atmosphere, biofuels have already been adopted as additives in traditional liquid fuels, being intended mainly for internal combustion engines of automobiles. The current work proposes an extension of biofuels application in combustion processes specific to industrial furnaces. This technical concern is not found in the literature, except for achievements of the research team involved in this work, which has performed previous investigations. A 51.5 kW-burner was designed to operate with glycerine originating from triglycerides of plants and animals, mixed with ethanol, an alcohol produced by the chemical industry recently used as an additive in gasoline for automobile engines. Industrial oxygen was chosen as the oxidizing agent necessary for the liquid mixture combustion, allowing to obtain much higher flame temperatures compared to the usual combustion processes using air. Mixing glycerine with ethanol in 8.8 ratio allowed growing flame stability, accentuated also by creating swirl currents in the flame through the speed regime of fluids at the exit from the burner body. Results were excellent both through the flame stability and low level of polluting emissions. 

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Open Access
Article
Article ID: 9729
by Xiaohong Gui
Therm. Sci. Eng. 2025, 8(3);    92 Views
Abstract

In order to meet the guidance, publicity and commercial functions, various types of billboards have become important permanent facilities in the airport terminal, which are distributed all over the terminal. The advertising materials inside billboards have certain fire hazards, and there is a lack of research on the fire risk of advertising materials at present. Therefore, it is necessary to study the fire risk of advertising materials in airport terminal. Taking PVC board, a commonly used advertising material, as the research object, Pyrosim was used to model and analyze its fire, and the characteristics of fire spread, smoke flow, and distribution of combustion products such as CO and CO2 in the terminal building were obtained. This study explores the fire combustion characteristics of advertising materials in civil airport terminals, providing a basis for fire prevention management in civil airport terminals.

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Open Access
Article
Article ID: 9186
by Wang Zhaofeng
Therm. Sci. Eng. 2025, 8(3);    93 Views
Abstract

The effective drainage radius of coal seam is an important basis for the spacing of pre-drainage gas boreholes. To quickly and accurately determine the effective drainage radius, a new method was proposed. For the coal face where the desorbable gas content before mining has met the standard, the compliance of mine gas drainage rate was used as the basis to determine the effective drainage radius. The fluid-structure interaction model was constructed, numerical simulation of coal seam gas drainage was carried out by using COMSOL software, and the model was validated by combining the field test results. The results show that the new method has the advantage of short cycle. With the extension of drainage time, the increase of effective drainage radius gradually decreases, and finally reaches a relatively stable limit value, which conforms to the Langmuir function. The average error between numerical simulation and field test values of effective drainage radius is 4.9 %, which proves that the model is reliable. This model can accurately predict the effective drainage radius under different coal seam gas contents and drainage times. The research results provide a new mean for determining the effective drainage radius of coal seam and the layout of gas drainage boreholes.

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Open Access
Article
Article ID: 9176
by Debashis Chatterjee, Subhrajit Saha
Therm. Sci. Eng. 2025, 8(3);    85 Views
Abstract

This research introduces a novel framework integrating stochastic finite element
analysis (FEA) with advanced circular statistical methods to optimize heat pump efficiency
under material uncertainties. By modeling directional variability in thermal conductivity
using both uniform and Von Mises distributions, the study highlights the superiority of the
Von Mises distribution in providing consistent and efficient thermal performance. The Von
Mises distribution, known for its concentration around a mean direction, demonstrates a
significant advantage over the uniform distribution, resulting in higher mean efficiency and
lower variability. The findings underscore the importance of considering both stochastic
effects and directional consistency in thermal systems, paving the way for more robust and
reliable design strategies.

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Open Access
Article
Article ID: 8258
by gudeta dawit
Therm. Sci. Eng. 2025, 8(3);    95 Views
Abstract

Biomass energy is abundant, clean, and carbon dioxide neutral, making it a viable alternative to fossil fuels in the near future.  The release of syngas from biomass thermochemical treatments is particularly appealing since it may be used in a variety of heat and power generation systems. When a syngas with low tar and contaminants is required, downdraft gasifiers are usually one of the first gasification devices deployed. It is time-consuming and impractical to evaluate a gasification system's performance under multiple parameters, using every type of biomass currently available, which makes rapid simulation techniques with well-developed mathematical models necessary for the efficient and economical use of energy resources. This work attempts to examine, through model and experimentation, how well a throated downdraft gasification system performs when using pretreatment biomass feedstock that has been characterized.

For the analyses, peanut shell (PS), a biomass waste easily obtained locally, was used. The producer gas generated with 9 mm PS pellets had a composition of 17.93% H2, 24.43 % CO, 12.47 % CO2, and 1.22 % CH4 on a wet basis at the value of 0.3 equivalency ratio and 800 °C gasification temperature. The calorific value was found to be 4.96 MJ/Nm3. The biomass feedstock PS is found to be suitable for biomass gasification in order to produce syngas.

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Open Access
Article
Article ID: 6734
by Danyang Li, Yunhui Yue, Jingqing Jiang, Jie Song
Therm. Sci. Eng. 2025, 8(3);    82 Views
Abstract

With the wide application of the Internet and smart systems, data centers (DCs) have become a hot spot of global concern. The energy saving for data centers is at the core of the related works. The thermal performance of a data center directly affects its total energy consumption, as cooling consumption accounts for nearly 50% of total energy consumption. Superior power distribution is a reliable method to improve the thermal performance of DCs. Therefore, analyzing the effects of different power distribution on thermal performance is a challenge for DCs. This paper analyzes the thermal performance numerically and experimentally in DCs with different power distribution. First, it uses Fluent simulate the temperature distribution and flow field distribution in the room, taking the cloud computing room as the research object. Then, it summarizes a formula based on the computing power distribution in a certain range by the numerical and experimental analysis. Finally, it calculates an optimal cooling power by analyzing the cooling power distribution. The results shows that it reduces the maximum temperature difference between the highest temperature of the cabinet from 5-7k to within 1.2k. In addition, the cooling energy consumption is reduced by more than 5%.

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