Papers by Yasser A . Jebbar
Thermo-hydraulic performance improvement inside parabolic trough receiver tube using passive techniques: A review
International Communications in Heat and Mass Transfer, 2025
Parabolic trough collector (PTC) converts the incident solar radiation into useful energy used in... more Parabolic trough collector (PTC) converts the incident solar radiation into useful energy used in many applications. Researchers in the past two decades focused on improving thermo-hydraulic performance inside a parabolic trough receiver (PTR) using various passive methods. These methods do not use an external power source to enhance the heat transfer. Twisted tapes, screws, rings, rods, and fins are passive turbulators inserted into the receiver tube to enhance thermo-hydraulic performance of PTR. On the basis of a study of published research, the present review evaluates, in depth, these passive methods used in enhancing the performance of a PTR and the consequent overall thermal performance of PTCs. Among the most remarkable findings, the ratios of the Nusselt numbers ( ∆ Nu) under different parameters varied between 1.1 and 7.42 with the values of the performance evaluation criteria (PEC) falling between 0.44 and 1.73 in various turbulator set-ups. As an example, a 2.5-fold enhancements in 5Nu are attained with twisted tapes with optimum twist ratios (23) and full porous discs that have up to 60 % enhancements in PEC. The heat transfer is also enhanced further by longitudinal fins (10–15 mm length, 2–4 mm thickness) with approximate values of 10Nu of 3.2. These results show the possibility of verification of a passive method to as well enhance the PTC efficiency largely. The review can be helpful to the researchers trying to maximize the utilization of solar energy in PTC systems.
Impact of vibration on thermal energy storage performance: A comprehensive review
International Communications in Heat and Mass Transfer, 2025
The recent review delves into exploring the effects of vibration on the behavior of thermal energ... more The recent review delves into exploring the effects of vibration on the behavior of thermal energy storage (TES) systems, with a particular emphasis on phase change materials (PCMs) and their implication in both mechanical and thermal systems. This examination discourses a serious challenge in the field: the request to improve heat transfer efficiency and upgrade energy storage rates in PCM-based systems. These systems are frequently facing a number of limitations as a result to slow phase transition rates and variations in the heat transfer process, which deter their overall performance. Indeed, an inspecting of how vibration can influence these parameters, this review intends to detect advanced strategies for enhancing the efficiency of PCMs in energy storage applications. The findings disclose that ultrasonic vibrations and mechanical vibrations can dramatically speed up the melting and solidification of PCM. As an example, in the case of non-vibration, the best option offered was I-shaped fin with fins count 8, which reached a peak temperature of 316.2 K and maximum temperature difference at 3.8 K. However, the performance further enhanced with vibration, where the maximum temperature drops by 6.5 % and the temperature difference declines by 18.7 % for 4 I-shaped fins, which ranks as the best options due to the ratio of cooling effectiveness, cost, and weight. Also, the experiment indicates that ultrasonic vibration made melting 2.5 times faster and energy consumption was 2.3 two 2.8 Wh lower than during natural melting. Recommendations stress the idea that vibration is a promising, energy-saving, and efficient way to optimise PCM functionality. However, some issues such as the selection of key parameters, and system hybridization still have to be removed. These findings can offer helpful suggestions towards planning and development of advanced knowledge in TES and management. Overall, this review is needed to secure more efficient thermal energy systems, eventually contributing to more sustainable energy solutions.
Discover Applied Sciences, 2025
Parabolic trough collectors often face efficiency losses due to limited heat transfer and high pr... more Parabolic trough collectors often face efficiency losses due to limited heat transfer and high pressure drops. This study numerically investigates the combined impact of ternary hybrid nanofluids and twisted tape inserts on thermal performance under turbulent flow (Reynolds number from 10,000 to 20,000). Using ANSYS Fluent, 15 models were developed with varying twisted tape configurations (0-4 inserts) and ternary hybrid nanofluid concentrations (0-24 wt%), assuming single-phase nanofluid flow under a 600 kW/m² non-uniform heat flux. Results show that the maximum Nusselt number improvement (44.3%) and friction factor enhancement (62.3%) occur in the model using 4 twisted tapes and 24 wt% ternary hybrid nanofluid. Also, the performance evaluation criterion reaches 1.219 using the optimal model with 2 twisted tapes and 24 wt% ternary hybrid nanofluids. These findings suggest that combining nanofluids and passive inserts can substantially enhance the thermal performance of parabolic trough collectors, guiding the design of next-generation solar receivers.
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Papers by Yasser A . Jebbar