Case Studies in Thermal Engineering最新文献

{"title":"Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic","authors":"Jiali Zhang ,&nbsp;Guangpu Zhao ,&nbsp;Umer Farooq ,&nbsp;Jifeng Cui","doi":"10.1016/j.csite.2025.105984","DOIUrl":"10.1016/j.csite.2025.105984","url":null,"abstract":"<div><div>This study investigates the unsteady thermal convective transport mechanism of nanofluids(Water-Al<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>) with couple stress in a circular microchannel under the influence of electromagnetohydrodynamic(EMHD) and time-periodic pressure gradients. The Poisson–Boltzmann(PB) equation related to potential is derived using the Debye–Hückel approximation. The velocity and temperature distributions are obtained using the Green’s function method, and the Nusselt number and entropy generation are further derived. The effects of different dimensionless parameters are shown graphically and analyzed and discussed. The main results indicate that increasing the dimensionless couple stress parameters significantly increases the velocity, temperature, and convective heat transfer efficiency of the fluid. In addition, as the dimensionless frequency increased, the fluid flow rate decreased, energy transfer became more efficient, and thermal irreversibility and energy dissipation are notably reduced. It is also found that in nanofluids with low nanoparticle volume fractions, an increase in nanoparticle volume fraction enhanced the convective heat transfer capability of the fluid. The novelty of this study lies in providing a systematic theoretical analysis of the thermal convection mechanism of nanofluids with couple stress under complex flow conditions, especially under the effect of EMHD and time-periodic pressure gradients. This study not only offers a new perspective for understanding the thermal convective behavior of nanofluids under special flow conditions but also provides significant theoretical insights for the optimization design of microchannel heat exchangers and related devices, which can contribute to improving overall performance and optimizing fluid flow and heat transfer characteristics.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 105984"},"PeriodicalIF":6.4,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulations of ice crystal icing within a 1.5-stage compressor in an aero-engine","authors":"Ping Huang ,&nbsp;Xueqin Bu ,&nbsp;Guiping Lin ,&nbsp;Dongsheng Wen","doi":"10.1016/j.csite.2025.106026","DOIUrl":"10.1016/j.csite.2025.106026","url":null,"abstract":"<div><div>Ice crystal icing within aircraft engines at high altitudes significantly impacts safe operation. Due to the complexity of the structure and the thermodynamic conditions, gaining a comprehensive understanding of ice crystal icing presents a considerable challenge. This study establishes a numerical simulation framework to investigate ice crystal icing in compressor structures, taking into account rotational effects and data transfer between blade rows. The simulation framework includes airflow field computation, particle movement model, and icing thermodynamic models. The icing process in a 1.5 stage compressor was simulated, revealing key insights into the ice accretion mechanisms. Results confirm that a certain range of temperature and pressure increases within the compressor causes ice particles to melt and stick to the blade surfaces, ultimately forming ice accretion. Ice accretion is primarily concentrated on the leading edge of the stator blades, with minor accretion on the pressure surfaces. The ice shapes exhibit pronounced three-dimensional characteristics in the spanwise direction due to centrifugal forces. Parameter influence analysis of the ice accretion reveals that temperature, particle size, and ice water content significantly affect the icing process. These findings provide valuable insights into the mechanisms of ice crystal icing in aero engines and contribute to the design of anti-icing systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 106026"},"PeriodicalIF":6.4,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the influence of pump frequencies and oil flow rates on the performance of organic rankine cycle systems","authors":"Jian Sun,&nbsp;Bin Peng","doi":"10.1016/j.csite.2025.106028","DOIUrl":"10.1016/j.csite.2025.106028","url":null,"abstract":"<div><div>The organic Rankine cycle system can fully utilize the low-temperature waste heat generated by oil-free scroll air compressors, enhancing energy reuse efficiency. The heat source temperature (HST), working pump frequency, and filling quantity of the working fluids varied to achieve variable operating conditions for the experimental system. Experimental studies showed that the working pump frequency has a significant impact on the theoretical shaft power of the expander compared to the HST and the filling quantity (FQ) of the working fluids. At a working fluid filling quantity of 8 kg and HST of 120 °C, increasing the working pump frequency from 10 to 50 Hz results in the theoretical shaft power of the expander, power consumption of the working pump, and the system thermal efficiency varying in the ranges of 0.993–1.777 <span><math><mrow><mtext>kW</mtext></mrow></math></span>, 0.063–0.143 <span><math><mrow><mtext>kW</mtext></mrow></math></span> and 4.979–6.436 %, respectively. While elevating the frequency of the working pump leads to a corresponding rise in the theoretical shaft power of the expander, it also increases the power consumption of the working pump. Lubricating oil has a considerable impact on system performance. At an HST of 120 °C, the net system work attains a maximum value of 2.093 <span><math><mrow><mtext>kW</mtext></mrow></math></span> with 100 % lubricant and pump plunger stroke (PPS).</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 106028"},"PeriodicalIF":6.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal energy optimization for electroosmotic flow of ternary nanocomposition with Debye-Hückel linearization approach","authors":"Saima Riasat ,&nbsp;Sumra Ali Khan ,&nbsp;M. Bilal ,&nbsp;Aceng Sambas ,&nbsp;Chemseddine Maatki ,&nbsp;Aboulbaba Eladeb ,&nbsp;Lioua Kolsi ,&nbsp;Badr M. Alshammari","doi":"10.1016/j.csite.2025.105996","DOIUrl":"10.1016/j.csite.2025.105996","url":null,"abstract":"<div><div>The current examinations incorporate the electroosmotic forces by considering the copper, aluminum, and carbon nanotubes as nanocomposites with water as the base fluid. Debye-Hückel linearization approach is utilized to study the electroosmotic forces. The effects of quadratically heated Riga plate and study of electric potential by using Gauss law of electricity induces the complex flow dynamics. The collocation technique is applied to seek the numerical solution of the coupled ODEs. It has been deduced that the thermophysical features are enhanced using ternary nanofluids, and the heat transfer effects of porous Riga plate exposed to the quadratic heated plate are more pronounced. Entropy generation analysis reveals that entropy is minimized by considering porous plate with electroosmotic forces in quadratically heated Riga plate.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 105996"},"PeriodicalIF":6.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of reactive fluid flow characteristics of high-energy propellants under periodic laser disturbance","authors":"Kaixuan Chen,&nbsp;Xiaochun Xue,&nbsp;Yonggang Yu","doi":"10.1016/j.csite.2025.105934","DOIUrl":"10.1016/j.csite.2025.105934","url":null,"abstract":"<div><div>During various missions involving solid rocket motors (SRMs), combustion instability poses a significant challenge, often leading to dangerous outcomes. To elucidate its mechanisms and enhance SRM design, this study investigates the reactive flow characteristics of non-aluminum NEPE propellants under periodic laser disturbances using a microscale model. The model integrates temperature-dependent condensed phase kinetics and gas-phase multi-flame interactions, revealing that surface morphology critically shapes gas product distributions near the surface, contributing to instability. Quantitative results demonstrate transient burning rate variations under different pressures (5–12 MPa) and laser powers (10–75 MW), with a maximum deviation of 5.67 % between simulations and experimental data. At 5 MPa, laser disturbance increases the transient burning rate by 20–35 % during energy application, while higher pressures (12 MPa) reduce thermal adjustment times by 40 % compared to lower pressures. Additionally, a critical laser power range (50–75 MW) significantly prolongs thermal stabilization durations. These findings provide insights into reactive flow dynamics under laser interference, supporting optimized propellant formulation and SRM design.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 105934"},"PeriodicalIF":6.4,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A desiccant evaporative air conditioning performance improvement using heat pipe heat exchanger as a heat recovery device","authors":"Adel Alblawi","doi":"10.1016/j.csite.2025.106027","DOIUrl":"10.1016/j.csite.2025.106027","url":null,"abstract":"<div><div>Desiccant evaporative systems represent promising alternatives to conventional air conditioners adopted for hot and humid climatic. Many desiccants augmented evaporative cooling systems have been reported in the literature. These systems include ventilation or conventional cycle, recirculation cycle, Dunkle cycle and regenerative heat exchanger cycle. The ventilation cycle is the earliest and probably the most commonly used in desiccant evaporative systems. In the present research, three new configurations are suggested and compared with the Traditional ventilation desiccant evaporative cooling system under different desiccants while inlet air temperature (28–46 °C) and air humidity ratio (0.01–0.02kg_wv/kg_da). A simulation model has been established and validated with the available experimental data in the literature of the traditional cycle. The comparison confirms that the assessment of the simulation model agrees with the experimental data and the obtained average errors of 1.74 % for temperature and 2.1 % for humidity ratio at the cycle state points. The energetic and exergetic analysis revealed that the suggested sys₁ has the same performance as the traditional system while the suggested sys₃ has higher thermal coefficient of performance (<em>COP</em>_<em>th</em>), exergy efficiency and air handling coefficient of performance (<em>COP</em>_<em>D</em>) than that of the other suggested systems. The <em>COP</em>_<em>th</em> of the traditional system changed from 0.442 to 0.3 while for suggested sys₃ it varied from 0.664 to 0.552 as an inlet temperature changed from 28 to 46 °C. However, as the inlet air humidity ratio increases from 0.01 to 0.02 kg_wv/kg_da the <em>COP</em>_<em>th</em> of the traditional system decreases from 0.55 to 0.26 while for suggested sys₃ decreases from 0.813 to 0.483. The system which uses the heat pipe heat exchanger and direct indirect evaporative cooler after the rotating heat exchanger (suggested sys₃) has higher performance than that of the other suggested systems from energetic and exergetic points of view.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 106027"},"PeriodicalIF":6.4,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energetic, economic and environmental (3E) analysis of R290, R454C and R465A for drop-in split type air conditioning running on R22","authors":"Carlos H.M. Braga ,&nbsp;Leonardo V.S. Martins ,&nbsp;Juan J.G. Pabon ,&nbsp;Luiz Machado ,&nbsp;Willian M. Duarte","doi":"10.1016/j.csite.2025.105988","DOIUrl":"10.1016/j.csite.2025.105988","url":null,"abstract":"<div><div>The present study aims to evaluate the process of drop-in of R22 in split type air conditioning with refrigerant fluids R290, R454C, and R465A. A mathematical model was developed to do an energetic, economic and environmental analysis using different fluids. The mathematical model of the heat exchangers was developed using the moving boundary technique and the compressor was modeled as recommended by the ISO9309 standard. The model was experimentally validated by comparing several results obtained in the laboratory using R22. The average absolute difference between experimental and theoretical results are 3.5%. R465A has cooling capacity 2.5% higher and R290 COP 8.1% higher than R22 in the test condition described by AHRI Standard 210/240. When taking into account cost, efficiency, and environmental effect, R290 is the most suitable replacement for R22 drop-in. R465A is the best option to replace the R22 when taking the cooling capacity results into account.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 105988"},"PeriodicalIF":6.4,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A hybrid CFD and machine learning study of energy performance of photovoltaic systems with a porous collector: Model development and validation","authors":"Yinling Wang ,&nbsp;Lei Yu ,&nbsp;Mazhar Ali ,&nbsp;Imran Ali Khan ,&nbsp;Tahir Maqsood ,&nbsp;Haining Gao ,&nbsp;Qi Wang ,&nbsp;Xiaolei Guo","doi":"10.1016/j.csite.2025.105998","DOIUrl":"10.1016/j.csite.2025.105998","url":null,"abstract":"<div><div>This study investigates the predictive modeling of temperature (T(K)) using a dataset of over 128,000 data points characterized by x, y, and z coordinates as inputs. The case study considered here is a photovoltaic system with porous collector for enhancing the efficiency of solar system. Computational modeling was carried out via CFD (Computational Fluid Dynamics), and the temperature distribution was determined which was later used in machine learning (ML) evaluation. Indeed, a hybrid model was developed combining CFD and ML for the first time to predict temperature distribution versus special coordinates in a photovoltaic thermal system. Three advanced machine learning models, i.e., Gradient Boosting (GB), Extreme Gradient Boosting (XGB), and Histogram-based Gradient Boosting (HGB) were applied to analyze and predict T in system. A systematic preprocessing pipeline was developed to enhance model performance, including outlier detection and feature normalization. Hyperparameter optimization process in this study uses the Water Cycle Algorithm (WCA), a metaheuristic method inspired by natural processes. Among the models, XGB emerged as the best performer, revealing a total R² of 0.99823, a Root Mean Square Error (RMSE) of 0.06596, and a Mean Absolute Error (MAE) of 0.04442. These results demonstrated the capability of machine learning to accurately capture complex relationships within structured datasets.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 105998"},"PeriodicalIF":6.4,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal transmission in thin film coating of ternary hybrid nanofluid over a rotating disk under magnetic field and nonlinear radiative effects","authors":"Qingwen Fu ,&nbsp;Zhimeng Liu ,&nbsp;Faisal Nazir ,&nbsp;Jawad Ahmed ,&nbsp;Abdullah Mohamed ,&nbsp;Ilyas Khan ,&nbsp;Mohamed Abdelghany Elkotb","doi":"10.1016/j.csite.2025.105978","DOIUrl":"10.1016/j.csite.2025.105978","url":null,"abstract":"<div><div>Applications for thin film flow are essential in many domains, including heat transfer systems, coating technologies, and microfluidics. Improvements in fields such as semiconductor manufacture, lubrication, and energy-efficient cooling are made possible by an understanding of thin film flow dynamics. Enhancing thermal conductivity by the use of nanofluids including nanoparticles such as MoS₂, CuO, and Al₂O₃ increases heat dissipation efficiency and system reliability. The thin film flow over a spinning disk of a ternary hybrid nanofluid (THNF) containing nanoparticles of MoS₂, CuO, and Al₂O₃ is the main subject of this work. The flow and heat transfer properties of the nanoliquid are examined in relation to a magnetic field, a Joule heating and nonlinear radiative heat flux. The resulting reduced ordinary differential equations are solved numerically in MATLAB through bvp4c solver. The findings indicate that faster heat transmission from the surface to the liquid is made possible by a thinner coating because of a steeper temperature gradient. Further, the study reveals that ternary hybrid nanofluids exhibit a superior energy transport rate compared to hybrid nanofluids at the disk's surface.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 105978"},"PeriodicalIF":6.4,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance analysis of control valves for a novel adsorption chiller with thermal energy storage","authors":"Tagne Takote Brice Clausel ,&nbsp;Cosmas Anyanwu ,&nbsp;Mkpamdi Eke ,&nbsp;Charity Mokom","doi":"10.1016/j.csite.2025.106015","DOIUrl":"10.1016/j.csite.2025.106015","url":null,"abstract":"<div><div>This study analyzed the control valve of an innovative solar-driven adsorption chiller, which regulates refrigerant flow during adsorption and desorption processes. The novelty of the system includes heat and mass recovery model working with thermal energy storage. Using Arduino Uno R3 and ANSYS Discovery, the control element of control loop was simulated and predicted by analyzing the valve's flow characteristics and thermal behaviour. The results showed good accuracy in time response for the on-and-off electromagnetic process. The optimal cycle times were determined as 360s for adsorption, 420s for desorption, and 50s for recovery model. The program code and simulation were then implemented into the hardware Arduino card to control the valve. The study found that the valve's structure and stroke were not affected by the maximum pressure and temperature of 9.989 kPa and 120 °C respectively. The amount of distortion energy obtained in terms of Von Mises stress was found to be 85100Pa. The results also showed a linear relationship between flow capacity and valve stroke, with a minimal pressure drop of 5 × 10⁻⁴ due to the small pipe diameter. Overall, this study can predict various scales adsorption chiller's time response and control valve's behaviour using heat and mass recovery model.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"69 ","pages":"Article 106015"},"PeriodicalIF":6.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}