Performance Evaluation Criteria Research Articles

Thermal enhancement of PEM fuel cell cooling with novel configurations of Tesla valve and hybrid nanofluids: A numerical study

The operating temperature and thermal distribution play a significant role in the appropriate performance of the proton exchange membrane fuel cell (PEMFC). A suitable cell cooling method can guarantee uniform temperature distribution and preservation of membrane water content under harsh conditions in a PEMFC. The compact structure of PEM fuel cells and the size of the cooling system impose a great challenge to achieve a proper design of cooling plate. In this numerical study, four designs of the multi-stage Tesla valve with straight and reverse configuration are proposed to be employed as a cooling channel in which three different hybrid nanofluids such as TiO2–Cu, Al2O3–CuO, and Ag–MgO dispersed in water and Ethylene glycol flow inside the channels. A validated numerical model is developed using a commercial computational fluid dynamics (CFD) code to investigate the effect of inlet temperatures and mass flow rates of cooling fluid and volume fraction of nanoparticles on heat transfer coefficient, pressure drop, index of uniform temperature (IUT), and performance evaluation criteria (PEC). The results demonstrated that the reverse configuration of the Tesla valve (CASE E) experienced outstanding uniform thermal distribution while the heat transfer coefficient increased by 15% in this case compared to the straight-line cooling channel. The Ag–MgO hybrid nanoparticles showed better thermal performance than the two other nanoparticles with a 4% reduction in temperature difference in the cooling plate.

An analysis of the impact of nanofluids on the cooling effectiveness of pin and perforated heat sinks

In the presented numerical study, the effect of the use of mono and hybrid (CuO/Water at 2% volume concentration and CuO + Fe/Water (1% CuO + 1% Fe)) type nanofluid in heat sinks designed in new geometric structures used to increase the processor cooling performance was investigated. The geometries used are circular, triangular, square, hexagonal, square, and hexagonal, and their perforated structures and their effects on a total of eight geometries were analyzed. In addition to these, the rate of improving the temperature distribution and heat transfer in the heat sink, i.e., the Performance Evaluation Criterion (PEC), was also examined. According to the results obtained, the lowest thermal resistance value is seen in the circular cross-section with Rth = 0.289 K/W, while the highest thermal, i.e., cooling performance is seen in the triangular perforated structure with Rth = 0.63 K/W and at the lowest pressure inlet condition. In terms of temperature distribution, the most uniform distribution was obtained between 311.82 and 308.98 K in the circular section. The most interesting result in terms of the results was the PEC = 1.4 for the triangular hole structure in the heat transfer improvement performance. The main reason for this is that the range of the temperature distribution shown is very high (319–311.5K).

Effects of airflow direction on the thermal-hydraulic performance of louvered fin-common flow up vortex generator

To improve the thermal-hydraulic performance of the louvered fin and flat tube heat exchangers (LFHEs), this paper innovatively proposes the louvered fin-common flow up vortex generator (LF-CFUVG). Then, numerical simulations are conducted to study the effects of airflow direction γ on the thermal-hydraulic performance of the LF-CFUVG. The corresponding results indicate that the flow resistance of the LF-CFUVG is always greater than the Baseline (the LFHE without CFUVGs), as the CFUVGs reduce the minimum free flow area while forming low-speed wake zones behind them. The heat transfer capacity of the LF-CFUVG exceeds the Baseline as well, this is attributed to the longitudinal vortices induced by the CFUVGs, which is helpful to homogenize the temperature field and transport the high-speed and low-temperature airflow. And the thermal-hydraulic performance of LF-CFUVG also outperforms the Baseline. In comparison to the working condition of γ is 0°, the pressure drop Δp for the LF-CFUVG declines with increase of γ from 0° to 30°, thus a larger angle helps to reduce flow resistance. However, the heat transfer coefficients hLF and performance evaluation criteria (PEC) of the LF-CFUVG deteriorate with the increasing γ, so a smaller angle is recommended to obtain an intenser heat transfer and better PEC.

Investigation of a hybrid two-layered channel-jet heat sink for air cooling

With the miniaturization and deep integration of electronics, the challenges associated with high-power heat dissipation technology have increased. Combining the features of jet cooling technology and microchannel cooling technology, a hybrid two-layered channel-jet heat sink is designed for general consumer CPUs. The heat sink performance is investigated experimentally. Since the CPU generation power is 120 W, the heat sink can control the CPU excess temperature below 60 °C with an air volume less than 20 m3/h and a pressure drop less than 20 Pa. The different geometric parameters of the heat sink are numerically calculated. Increasing the channel width and reducing the channel height and slot length can enhance the heat transfer but also increase the pressure drop. Orthogonal tests are employed to optimize the design by evaluating the performance of various heat sink structures. The performance evaluation criterion (PEC) is selected as the evaluation index. Under standard conditions with a cross-sectional airflow velocity of 1.5 m/s, the optimal structure is a 2 mm channel width, 12 mm channel height and 50 mm slot length.

Heat transfer enhancement in a triple-layered turbine blade internal cooling channel

An effective measure of enhancing the coupled convection and radiation in the turbine blade internal cooling channel is developed. A triple-layered channel is presented for the first time to further improve the flow organization to suppress the negative effect of secondary flows induced by rotation as well as extend cold surfaces for radiation. Explorations of flow and coupled heat transfer are executed numerically for various channel models. The results manifest that, heat transfer is markedly improved with the triple-layered channel. The highest comprehensive thermal performance is achieved when employing the triple-layered channel with smooth surfaces and ribs (Model 3SW), which can increase the total Nusselt number ratio by 105.78 % and performance evaluation criterion by 18.75 %, comparing with the existing Model 1 N. Besides, the average and maximum wall temperature drop by 54.26 K and 293.02 K, respectively. In addition, the triple-layered channel is demonstrated to have the ability to reduce rotational effects on heat transfer uniformity. The heat transfer difference between the leading and trailing walls induced by the Coriolis force is restricted. It also has the self-adaptive ability to increase the degree of heat transfer enhancement when thermal load increases.

Comprehensive numerical investigation of the effect of various baffle design and baffle spacing on a shell and tube heat exchanger

This article explores the significance of Shell and Tube Heat Exchangers (STHX), with a focus on various baffle types such as Segmental, Double segmental, Helical, Disc-and-Doughnut, Clamping anti-vibration, and Flower-B. In this study, the commercial software ANSYS FLUENT is used to simulate the problem. The study evaluates their impact on heat exchanger performance using parameters like overall heat transfer coefficient (OHT), pressure drop (PD), and Performance Evaluation Criteria (PEC). Clamping anti-vibration, Flower-B, Helical, and Double segmental baffles exhibit reductions in shell side PD by 14%-28%. Despite OHT reductions in these designs, Disc-and-Doughnut baffles demonstrate a higher OHT (21%-24%) compared to Segmental baffles. Based on PEC values, Disc-and-Doughnut baffles are identified as the most favorable. Further investigation into different numbers of Disc-and-Doughnut baffles reveals increased OHT (17%-29%), PD (58%-59%), and cold water temperature (0.5%-1%). The STHX with Disc-and-Doughnut 10 baffles displays the highest PEC value, establishing it as the most effective STHX in the simulation.

Integrating deep transformer and temporal convolutional networks for SMEs revenue and employment growth prediction

Although the accurate potential for growth prediction is very important for Government grants and contributions programs to better support Small and Medium-sized Enterprises (SMEs), it is a challenging task due to the data heterogeneity (both structured data and free text data bilingual in English and French), the class imbalance issue, and the difficulties in efficient feature learning. To address these challenges, this paper presents a novel BERT-TCN model for portfolio predictions in government funding programs, with the following key contributions. First, we describe the application of a novel architecture to a prediction task involving sequential, structured, partially quantitative input data and free text input data. Specifically, our novel model predicts the growth of firms receiving government funding for innovation. Our model also deals with class imbalance in the data and the difficulties in efficient feature learning. Our model integrates a Transformer model, i.e., BERT, for text modeling with a Temporal Convolutional Network (TCN) for sequential prediction. Second, we also developed various performance evaluation criteria in Section 4.3, allowing comprehensive assessments of the proposed approach from both the machine learning perspective and funding program-specific perspective. Third, the importance of features (both text and numerical features) is quantified and evaluated, allowing insights into how different features contribute to the prediction and explainability of the proposed model. The proposed approach is trained and tested on a large dataset from a rich database, demonstrating that the proposed approach can greatly help individual human experts improve their results.

Experimental investigation of the effects of graphene nano particle added water fluid on heat transfer in a smooth tube with double inserts

In this study, experimental studies were carried out to increase the performance of heat exchangers. The effects of two techniques (inserts and nanofluid) on thermohydraulic performance was investigated simultaneously. The twisted tape and the helically wire coil were originally created. The two separation ratios (0.1 and 0.05), the eight twisted tape pitch ratios (1.9/2.3/2.7/3 and 2.1/2.4/2.8/3.2), the four coil wire pitch ratios (0.8/1.2/1.5/1.6) and three weight fractions (0.5/0.75/1 %) for graphene-water nanofluids were used with the Reynolds number ranging from 5000 to 26,000. Experiments in which a coiled wire coil and twisted tape are used together have been found to increase both the heat transfer rate and the friction factor compared to experiments using distilled water in an empty tube. According to the results of all experiments, it was found that the highest heat transfer rate and friction factor were obtained with the model containing graphene-water fluid used at a weight fraction of 1 %. The highest performance evaluation criteria is found as 2.5 b y using the graphene-water mixture model with a wall separation ratio of 0.05, a twisted tape ratio of 2.1, a wire coil ratio of 0.8 and a 1 % weight fraction among all combinations.

FORECASTING THE CONSUMPTION OF ELECTRICAL ENERGY ON THE CEB ELECTRICAL NETWORK IN LOME IN TOGO BY APPROACHES: SIMPLE LINEAR REGRESSION, RECURRENT NEURAL NETWORKS AND GENETIC ALGORITHMS

Forecasting the electrical power to be consumed requires planning production on several levels. In this work we used data from the Electric Community of Benin. Temperature, relative humidity, wind speed, normal direct irradiance, precipitation and diffuse radiation are the meteorological variables that made it possible to analyze the forecasts. The objective is to do learning with genetic algorithms, LSTM recurrent neural networks and simple linear regression after a characterization and a correlation study and then to submit the results to performance evaluation criteria. The results of the characterization made it possible to understand that certain variables are significant and influence the consumption of electrical energy. The study of the correlation gives 94% between direct normal irradiance and diffuse irradiance. Both give with the temperature 67% for one and 68% for the other. Regarding modeling, the results are bad with genetic algorithms if we take into account the correlation coefficient (R² = 28.84%), good with simple linear regression (R² = 69.08%) and very interesting for networks of recurrent neurons where we find: MAE = 0.11 MSE = 0.02 MAPE = 18.50% RMSE = 13.09% RRMSE = 18.25% and R² = 96.11%. Given these results, we deduce that short- and long-term memory recurrent neural networks (LSTM) are very well suited to predicting the electrical power consumed on the CEB electrical network.

Experimental investigation of shell and helical coiled heat exchanger with Al2O3 nano-fluid with wide range of particle concentration

The purpose of this study is to experimentally enhance the heat exchange rate of the shell and helical coil tube heat exchanger by mixing water with aluminum oxide (Al2O3) nanoparticles, as well as to explore the effect of inlet thermal parameters on the performance of the heat exchanger. A test rig was constructed to investigate the influence of particle concentration, and inlet temperatures on the performance of nano-fluid. Parameters such as Nusselt number, pressure drop, performance evaluation criteria (PEC) are considered to rate the performance of the nano-particle with the heat exchanger. In this study a wider range of particle concentration is considered, which varies from 0.0%–0.75%. Experiments with and without nanoparticles are carried out under identical working conditions. By analyzing the experimental data, it was found that nanoparticles significantly improve the coefficient of heat transfer inside the helically coiled tube. From sensitivity analysis, it is obseerved that there is a slight decrease in Nusselt number of the nano-fluid with increase in inlet temperatures of the nano-fluid and the cooling water. Furthermore, it is concluded that an 8.5% increase in PEC value is observed with increase in particle concentration from 0.15% to 0.75%.

A Hybrid Multi-Agent Reinforcement Learning Approach for Spectrum Sharing in Vehicular Networks

Efficient spectrum sharing is essential for maximizing data communication performance in Vehicular Networks (VNs). In this article, we propose a novel hybrid framework that leverages Multi-Agent Reinforcement Learning (MARL), thereby combining both centralized and decentralized learning approaches. This framework addresses scenarios where multiple vehicle-to-vehicle (V2V) links reuse the frequency spectrum preoccupied by vehicle-to-infrastructure (V2I) links. We introduce the QMIX technique with the Deep Q Networks (DQNs) algorithm to facilitate collaborative learning and efficient spectrum management. The DQN technique uses a neural network to approximate the Q value function in high-dimensional state spaces, thus mapping input states to (action, Q value) tables that facilitate self-learning across diverse scenarios. Similarly, the QMIX is a value-based technique for multi-agent environments. In the proposed model, each V2V agent having its own DQN observes the environment, receives observation, and obtains a common reward. The QMIX network receives Q values from all agents considering individual benefits and collective objectives. This mechanism leads to collective learning while V2V agents dynamically adapt to real-time conditions, thus improving VNs performance. Our research finding highlights the potential of hybrid MARL models for dynamic spectrum sharing in VNs and paves the way for advanced cooperative learning strategies in vehicular communication environments. Furthermore, we conducted an in-depth exploration of the simulation environment and performance evaluation criteria, thus concluding in a comprehensive comparative analysis with cutting-edge solutions in the field. Simulation results show that the proposed framework efficiently performs against the benchmark architecture in terms of V2V transmission probability and V2I peak data transfer.

Evaluation of nanoparticle shape factor on a laminar forced convective heat transfer characteristics of various nanofluids flow in a tube using single-phase numerical model

Nanotechnology is advantageous in improving thermophysical properties and enhancing heat transfer rate compared with conventional fluids due to their superior thermophysical properties. These properties vary with many parameters such as concentration and shape. In this study, the effect of nanoparticles shape is numerically explored on heat transfer performance under a laminar flow regime (Re=500 and 2000) through the smooth tube. Heat transfer enhancement capability of the nanoparticle shapes with targeted reference to average Nusselt number, average Darcy friction factor, pumping power, and performance evaluation criterion have been investigated. Three types of nanofluids (Fe3O4/water, Al2O3/water, and GO/water) with various nanoparticle shapes (brick, cylindrical, platelet, and spherical) and different nanoparticle volume fractions (φ=1.0, 2.0, 3.0, and 4.0%) have been used as heat transfer fluid in analyzes. Numerical results show that heat transfer performance was greatly influenced by changing nanoparticle shapes. The highest average Nusselt number was obtained for GO/water nanofluid with platelet nanoparticle shape and φ=4.0%. Compared to water, Fe3O4/water, and Al2O3/water, the average Nusselt number in GO/water increased by 64.34%, 54.02%, and 43.41%, respectively. The highest performance evaluaton criterionwas obtained for the GO-water nanofluid with platelet nanoparticle shape at Re=2000. On the other hand, it is found that the Fe3O4/water nanofluid with platelets nanoparticle shape causes the highest pumping power compared with other analyzed nanofluids.

Numerical investigation of the thermal-hydraulic performance of a novel parabolic trough wavy tubular receiver by using FMWNCT/oil-nanofluid coupled with fins

This study employs a computational fluid dynamics (CFD) approach to assess the performance of a novel wavy profile tube receiver. It integrates rectangular fins and an Oil-based nanofluid, specifically utilizing Thermodyne GG-03 synthetic oil combined with Functionalized Multi-Wall Carbon Tubes (FMWNCT). The synthesis involves rigorous experimental procedures to characterize the thermophysical properties of the oil and nanofluid. Empirical correlations, validated against Bitam et al.'s model [1], guide the numerical analysis. The investigation, utilizing a steady-state κ - ω SST turbulence model with a non-uniform Gaussian thermal flux distribution, explores thermohydraulic performance in fully developed turbulent flow (Reynolds number range: 2 × 104 – 5 × 104). Comparative analysis with Bitam et al.'s work, employing Syltherm 800 oil as a reference, reveals a 25.76% average Nusselt number enhancement with Thermodyne GG-03. Additional improvements are observed: 124.69% with FMWNCT/oil-nanofluid, 137.04% with fins, and 236.54% with combined FMWNCT/oil-nanofluid and fins. These enhancements lead to increased heat transfer coefficients and rates. The friction coefficient rises by less than 60%, mainly attributed to the Nusselt number improvement. At RE = 20000, the Maximum Performance Evaluation Criteria (PEC) is 5.5, signifying significant improvement. Notably, a 300% PEC enhancement is observed compared to Roger and Mayhew's curved tube model [1]. In conclusion, these findings offer valuable insights for efficiently designing wavy tubular receivers in PTR collectors.

Two-phase simulation of hydrothermal performance and entropy generation aspects of a biologically prepared nanofluid-cooled heat sink with helical Tesla valve-based microchannels

The continuous development of innovative cooling techniques is imperative for advancing electronic device performance, enhancing efficiency, and prolonging their operational reliability in an ever-evolving technological landscape. In this numerical investigation, the hydrothermal performance and entropy generation aspects of a heat sink featuring Tesla valve-base helical channels are explored using the two-phase mixture method. The chosen heat transfer fluid is a water-silver nanofluid synthesized through a biological method. The study delved into the impact of Reynolds number (Re = 500–2000) and nanofluid concentration (φ = 0–1%) on the system's functional parameters, and the results are subsequently compared with data associated with a heat sink employing the helical plain channels. It was uncovered that elevating Re and diminishing φ result in improved central processing unit (CPU) cooling, lowered thermal resistance, and a reduction in the temperature differential between the maximum and minimum CPU temperatures. Meanwhile, the pumping power of nanofluid increases with higher Re s and lower φ s. Furthermore, it was discovered that the overall hydrothermal performance of the heat sink with Tesla valve-type helical channel consistently surpasses that of the heat sink with helical plain channel. The peak value of the Performance Evaluation Criterion, reaching 1.642, was associated with Case Re = 500 &φ = 0 %. Furthermore, it was found that substituting the Tesla valve-base channel for the plain channel results in a decrease in the total entropy generation up to a Re of 1500.

The Sustainable Development Goals for Education and Research in the Ranking of Green Universities of Mahasarakham University

This research aims to review the educational and research operations of Mahasarakham University and propose development directions for the university to meet the sustainable development criteria for ranking as a green university. This involves gathering data and analyzing the results of operations over the past 3 years, then using this analysis to synthesize the lessons learned and develop guidelines for sustainable development in the coming years. The study utilizes a robust methodology involving policy analysis, strategic planning, performance evaluation, and data integration. The study found that the university’s policies and strategies implemented following the annual performance evaluation criteria align with the green university assessment criteria for education and research. This has resulted in minor improvements in the curriculum for sustainability. However, community service projects for sustainability have increased by 89.10%, while funding for sustainable research and academic publications related to sustainability has decreased. In summary, the projects under the university’s development strategy adequately support and drive suitable development activities. Nevertheless, the university must continuously review its operations to adapt to changing contexts, budget constraints, evolving competition, and long-term development towards the implementation of the sustainable development goals (SDGs) to develop in the future.

Employing uniform and non-uniform inner twisted elliptical tubes in a double-pipe heat exchanger

Turbulent hydrothermal characteristics in a double-pipe heat exchanger with an internal twisted elliptical tube (TET) are investigated. The impacts of aspect ratio (AR = 1.4–2), uniform twist pitch (p = 100 mm-400 mm), and non-uniform twist pitch (five cases) on flow stream characteristics and heat transfer of parallel and counter-flows are investigated numerically. Utilizing a TET with a non-uniform twist pitch as an innovative approach yields noteworthy results, particularly in contrast to the traditional use of TETs with uniform twist pitch, owing to the longitudinal asymmetry. The outcomes depict that the pressure drop and heat transfer augment as the uniform twist pitch declines and the AR rises. The counter-flow has a more significant average Nusselt number than the parallel-flow by about 2–4 % without increasing the friction factor. Still, in some cases of non-uniform twist pitch, the average Nusselt number of the parallel flow is even 4 % higher than the counter-flow. The case with p = 100–200–400 mm (three parts with various twist pitches) and parallel-flow exhibits the most significant performance evaluation criterion (PEC) among the non-uniform twist pitch. As the aspect ratio increases from AR = 1.4 to AR = 2, the PEC factor in the counter-flow mode increases; however, there is an out-of-trend point at AR = 2 for the parallel-flow mode. The PEC factor augments about 8.47 % and 6.16 % for the counter-flow and the parallel-flow modes, respectively. The growth of TET twist pitch by 300 % reduces PEC by about 13.3 % in the counter-flow. The most significant PEC value is 1.166, which belongs to the case with the counter-flow condition and p = 100 mm.

Thermohydraulic analysis of nanofluid flow in tubular heat exchangers with multi-blade turbulators: The adverse effects

Based on the significance of heat transfer in tubular flows, various methods of heat transfer enhancement have been developed by scholars. The use of turbulator inserts like twisted tapes is widely discussed and suggested by researchers, and many studies have concentrated on the positive influence of these devices. However, the question is whether these devices always positively impact heat transfer and fluid flow. In this study, efforts were made to find possible adverse impacts of using twisted tapes on the average Nusselt number (Nu), friction factor (f), flow behavior, and performance evaluation criterion (PEC) of water-titania nanofluid. Three-dimensional (3D) numerical methods were used to assess a combination of three different configurations of 156 cases with/without turbulators with different numbers of blades and pitch ratios (PR). Results suggest that at Reynolds number (Re) = 4000, 6000, and 8000, only 25 %, 25 %, and 22.9 % of the examined cases led to PEC values over 1. Based on the results, while twisted tapes raised the Nu by up to 65.1 %, the f can be increased by up to more than six times. Furthermore, streamlines and velocity magnitude contours were employed to discuss the fluid flow behavior in the presence of the turbulators. According to the findings, while with the best turbulator, the PEC value was increased by only 6.3 %, some of the turbulators reduced this parameter by up to 11.8 %, which is more severe. The worst performance was observed with the Case C (three-bladed) turbulator at a PR value of 11, which reduced the PEC by 11.8 %.

Enhancing supercritical carbon dioxide heat transfer in helical tube heat exchangers with twisted tape inserts: A computational investigation

Supercritical carbon dioxide (sCO2) has recently gained considerable attention due to its unique thermal properties that make it favorable as working fluid in various thermal system. It is particularly promising in cooling application of powerplant in combination with helical tube heat exchanger. One way to further enhance its heat transfer performance is by introducing twisted tape insert to the helical tube heat exchanger working with sCO2. Nonetheless, no study evaluating this idea has been reported, withholding further implementation of this innovative idea. Hence, this study aims to investigate the heat transfer performance of sCO2 in helical tubes with twisted tape inserts. A three-dimensional computational model, considering mass, momentum, and energy conservation, is developed and validated against experimental data. The heat transfer characteristics are evaluated in terms of wall and bulk fluid temperature as well as heat transfer coefficient. The impact of twisted tape width, twisting turns, and operating parameters (heat and mass fluxes) are evaluated to gain understanding on the contribution of these parameters on the heat transfer mechanism of the flow. The results reveal that introduction of twisted tape inserts enhanced heat exchange performance because of the intensified secondary flow within the helical tube. The most notable enhancement takes place when the temperature remains within the pseudo-critical region, driven by the higher thermal conductivity that dominates heat transfer near the wall and the higher specific heat capacity, enabling efficient heat absorption while restraining temperature rise. However, increasing the number of turns and tape width does not necessarily result in a greater heat transfer enhancement. Performance evaluation criterion (PEC) is utilized to evaluate overall performance. Further exploration using the Taguchi method underscores the dominance of operating parameters including mass flux and heat flux, over geometric factors like the number of turns and tape width. Moreover, strong interactions are only observed between geometric parameters (number of turns and tape width) and the temperature difference between the inlet and pseudo-critical points. Results from this study are expected to augment critical information required in developing high performance cooling mechanisms for various thermal systems, especially power plants.

Numerical study on cooling characteristics of turbine blade based on laminated cooling configuration with clapboards

The double-wall configuration, characterized by its notable overall cooling effectiveness, serves as a pivotal reference configuration in the design of next-generation turbine blades. In this study, a laminated cooling configuration with clapboards is developed, based on insights derived from both double-wall cooling configuration and laminated cooling configuration. Through a comparative analysis, with the double-wall cooling configuration and laminated cooling configuration as benchmarks, the newly constructed configuration is capable of enhancing overall cooling effectiveness while maintaining control over total pressure loss in the study. Specifically, in the context of external film cooling with an adiabatic condition, the laminated cooling configuration with clapboards attains the highest value at low blowing ratios, while the laminated cooling configuration excels in average adiabatic film cooling effectiveness at high blowing ratios. Importantly, the inclusion of clapboards significantly improves the internal heat transfer area, resulting in a greater internal total heat exchange in the laminated cooling configuration with clapboards. Consequently, this proposed configuration achieves the highest overall cooling effectiveness, achieving increases of 9.02%–14.08 % and 2.77 %–3.54 % relative to the double-wall cooling configuration and laminated cooling configuration, respectively. A comprehensive performance evaluation criterion is applied to assess cooling effectiveness and pressure loss. The results indicate that the laminated cooling configuration with clapboards enhances heat transfer effectiveness while effectively controlling pressure drop, with an evaluation value of over 1.0. Furthermore, the overall cooling effectiveness of the three cooling configurations is compared at two Reynolds numbers. It is found that the proposed configuration exhibits the best cooling performance, especially at the high Reynolds number.

Investigating the Impact of Flow Profile on Heat Transfer in Nanofluid Flow: A Numerical Study

Assessing the profitability of an energy system requires careful consideration of various factors, including fluid characteristics, geometry shape, and operating conditions. This study investigates the influence of sinusoidal rib shapes, with different space ratios (e/b) ranging from 0 to 1, on heat transfer in nanofluid flow. The channel's upper surface is subjected to a uniform heat flux, employing Al2O3 nanofluid as the working fluid and varying Reynolds numbers from 5000 to 20000. Additionally, the effect of aluminum nanoparticle volume fraction, ranging from 0 to 6%, is analyzed. Simulation results indicate that the performance of the corrugated surface in the channel is significantly influenced by rib shapes and their geometrical parameters. The highest Performance Evaluation Criteria (PEC) index is achieved for ribs with a space ratio (e/b) of 0 at Reynolds number of 5000 and a volume fraction of 6% nanoparticles. Furthermore, the average Nusselt number shows an increasing trend with higher particle volume fraction and Reynolds numbers.