@article { author = {Delkhosh, M. and Aliramezani, M. and Irannejad, M. and Lashgarian Azad, N.}, title = {Optimal control of hybrid electric vehicles by considering engine and tire/road noises}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3129-3140}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56065.4535}, abstract = {Along with exhaust emissions and fuel consumptions (FCs), noise emission from cars is one of the main concerns of the automotive industry. Hybridization is a promising method not only to make automobiles more environmentally-friendly, but also to reduce their noise emissions. However, a proper control design for hybrid electric vehicles (HEVs) to make noise emissions lower is still required in addition to exhaust emissions and FC reductions. In this study, we modify Equivalent Consumption Minimization Strategy (ECMS) to keep the engine noise less than tire/road noise during driving. A test bench is established for calculating the engine noise and brake specific fuel consumption. Moreover, the tire/road noise is experimentally defined as a function of the vehicle speed. It is shown that implementing the basic ECMS, the engine noise exceeds the tire/road noise in some moments of driving cycle, which is annoying to the passengers. Therefore, a modified ECMS is proposed to limit the candidate engine operating points such that the engine noise does not exceed the tire/road noise. It is shown that the engine noise level is kept below the tire/road noise level by using the modified ECMS at the expense of a very small increase in the vehicle’s FC.}, keywords = {Hybrid electric vehicle,noise emission,equivalent consumption minimization strategy,fuel consumption,engine noise,tire/road noise}, url = {https://scientiairanica.sharif.edu/article_22347.html}, eprint = {https://scientiairanica.sharif.edu/article_22347_d3312c3ef747cc01601fd2553a69b61c.pdf} } @article { author = {Narimani, M. and Abbassi, A.}, title = {Numerical and experimental analysis of the air distribution system in a data center building to improve the thermal performance}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3141-3155}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56116.4554}, abstract = {The purpose of the management of air distribution systems is to solve the problems in the cooling of data centers through minimizing the hot air recirculation and cold air bypass. In this paper, experimental and numerical analyses are conducted for the AUT data center. The data center performance indices have been compared between experimental and numerical solutions. According to temperature contours at a height of 1 m from the raised floor, recirculation of hot air to the cold aisle enclosure has occurred. For enhancement, the thermal management of the data center, cold aisle enclosure with decreasing supply airflow temperature to 18 , and hot aisle enclosure with return hot air from plenum ceiling to CRAC units were investigated. With the decrease in the total airflow supplied by CRAC units in the cold aisle enclosure and hot aisle enclosure models, the problem of Super-micro servers that experience about 50% more airflow than defined airflow for them in the base model, has been solved. The load on the cooling systems decreased from 13.2 kW up to 7.8 kW in hot aisle containment, the result is a hot aisle is a more suitable and appropriate configuration for the data center}, keywords = {Data centers,numerical simulation,Thermal management,Raised floor,Aisle containment}, url = {https://scientiairanica.sharif.edu/article_22348.html}, eprint = {https://scientiairanica.sharif.edu/article_22348_22062debb0b319d55036dc2c12875f86.pdf} } @article { author = {Ahmad, N. and Zheng, Q. and Fawzy, H. and Lin, A. and Jiang, B.}, title = {CFD investigation of an axial compressor with casing treatment for the enhancement of the stall margin}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3156-3167}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56486.4742}, abstract = {Casing treatment is an efficient technique that is used to increase the compressor stall margin with a minor reduction in efficiency. The interaction between the blade passage and the groove is the main cause of the stall margin improvement by various researches. A numerical study is conducted on a single circumferential casing groove using NASA rotor 37 in the current study. The performance of the two circumferential groove models is studied by discretizing RANS 3D equations using a finite volume technique. The inception of the stall is predicted according to the criteria of convergence. Two models of the circumferential groove have been suggested and numerically tested. A single passage simulation is selected for the two models. The performance of the smooth casing and the two models are analyzed. Moreover, the stall margin, total pressure ratio, and peak adiabatic efficiency of the normal casing, and the two models are analyzed to determine the influence of the groove on the axial compressor performance and stability. Models 1 and 2 stall margins are enhanced by 6.62 % and 4.45% respectively. The adiabatic efficiency of model 1 and model 2 are decreased by 0.79 % and 1.08 % respectively.}, keywords = {Axial compressor,adiabatic efficiency,Computational Fluid dynamics,casing groove,numerical simulation,stall margin}, url = {https://scientiairanica.sharif.edu/article_22271.html}, eprint = {https://scientiairanica.sharif.edu/article_22271_923633bc7eb2f4a2bc8011a767298e2c.pdf} } @article { author = {Parvaresh, A. and Mardani, M.}, title = {Adaptive predictive control for torque applying system of high-powered test rig}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3168-3180}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56413.4711}, abstract = {This paper proposes the implementation of a novel predictive control scheme known as adaptive generalized predictive control (AGPC) in the actuation system of a high-powered test rig. Through the use of actuation system, the required torque for simulating different conditions can be applied to the tested gearboxes. The accurate and precise control of this system is of great importance as it affects the overall performance of the test rig. The considered actuation system in this investigation is electro-hydraulically driven with nonlinear and uncertain characteristics. The performance of the proposed control scheme in different conditions of the parametric uncertainty as well as presence of disturbances are evaluated and the results are discussed. The results confirmed the superior performance of the proposed scheme in different studied conditions.}, keywords = {mechanically closed-loop test rig,predictive control,Torque applying system,Adaptive Control,Parameterized identification}, url = {https://scientiairanica.sharif.edu/article_22228.html}, eprint = {https://scientiairanica.sharif.edu/article_22228_edf6fea33b5ecf8d7ab3a2b4131cf906.pdf} } @article { author = {Kumar, M. and Ansari, N. A. and Sharma, A. and Singh, V. K. and Gautam, R. and Singh, Y.}, title = {Prediction of an optimum engine response based on different input parameters on common rail direct injection diesel engine: A response surface methodology approach}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3181-3200}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56745.4885}, abstract = {As the pollution standards have been raised, the reduction of harmful pollutants is of considerable significance to the transportation industries. The primary aim of this study is to use the response surface methodology (RSM) to optimize pollutants and efficiency to achieve the optimum configuration parameters for the engine. The findings reveal that the RSM technique is a highly desirable optimization approach that can save a lot of repetitive testing. The optimization of variables was conducted using RSM's desirability method such that the performance of the engine gets maximized along with CO2 while reducing the emission factor to a minimum range such as hydrocarbon (HC). After RSM modelling it was observed that the optimized engine settings of input factors are diesel/linseed blend ratio 8.10%, FIP 600 bar, EGR 4.667%, and load on engine 9.33kg. On these constant hold values, the optimized output torque, BTE, BMEP, mechanical efficiency, HC, and CO2 have obtained 20.04 Nm, 26.035%, 3.474 bar, 52.503%, 28.14ppmv, and 7.319 %vol. respectively. Aforesaid predicted values were validated experimentally and errors in predicted values are in a limited range. To achieve improved results, the arrangement of other biodiesel blends from different sources can be carried out for future work.}, keywords = {Linseed,Biodiesel,Blend,performance,Emission,CRDI,RSM}, url = {https://scientiairanica.sharif.edu/article_22272.html}, eprint = {https://scientiairanica.sharif.edu/article_22272_f3ae1a2719e5e0b108fb49e7fe28b0cf.pdf} } @article { author = {Tayyab, M. and Imran, M. and Rafai, A.}, title = {Experimental investigation of open-hole compression strength of carbon epoxy composite material and determination of localized strains using digital image correlation technique}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3201-3215}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.57044.5034}, abstract = {The biggest application of the fiber-reinforced composites are in the field of military and commercial aircrafts. Carbon fibers either alone or with the Kevlar 49 fibers, are widely used as main material in many aero plane wing, fuselage and empennage components. Composites materials have wide applications in different industries because of it has very different properties from the metals and polymers. In the drilling of Carbon/Epoxy Composites the cut surface quality is very much dependent on the drilling parameters set during drilling which further effect the strength of the hole during extension/compression loading. In this research, Carbon Fiber Epoxy Composite material is drilled with the standard carbide drill bit and Open Hole Compression (OHC) tests are performed on the Universal Testing Machine. The Digital Image Correlation (DIC) technique is used to find out the strain distribution around the hole during compression loading. From the experimental method and DIC, maximum strength of carbon epoxy composite is achieved by drilling at 1600-2400 mm/min in presence of notch. It was also observed that failure of the structure is dependent on the drilling feed rate and 1600-2400 mm/min was the optimized drilling range.}, keywords = {Composite Materials strength,Carbon Epoxy Composite,Digital Image Correlation,Carbon fibers}, url = {https://scientiairanica.sharif.edu/article_22351.html}, eprint = {https://scientiairanica.sharif.edu/article_22351_795e42e9cce1b118f6bdfd4c99318e89.pdf} } @article { author = {Golkar, S. H. and Khayat, M. and Zareh, M.}, title = {Experimental study of heat transfer characteristics of nanofluid nucleate and film boiling on horizontal flat plate}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3216-3231}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56967.4997}, abstract = {In this paper, the heat transfer characteristics of nanofluids nucleate and film boiling is studied experimentally. For this purpose, Al2O3 and SiO2 deionized water-based nanofluids prepared with three volumetric concentrations of 0.1%, 0.3% and 0.5%. The boiling experiments were conducted on a circular and polished copper surface with a diameter of 25 mm. The results showed that the addition of nanoparticles to the base fluid reduced the heat transfer coefficient of nucleate boiling. The boiling of nanofluids increased the surface wettability and the critical heat flux was significantly higher than that of pure deionized water. The Al2O3 deionized water-based nanofluid with a volumetric concentration of 0.5% had the best performance, with a critical heat flux of 44.56% higher than that of pure deionized water. The presence of nanoparticles in the deionized water-based nanofluid improved the heat transfer coefficient of film boiling. The results showed that the stable film boiling for nanofluids starts at higher wall superheat temperature difference than pure deionized water. Among the investigated concentrations, volumetric concentration of 0.5% had best performance for both nanofluids, so that the minimum heat flux of Al2O3 and SiO2 deionized water-based nanofluids were increased 35.01% and 34.40% compared to pure deionized water, respectively.}, keywords = {Nucleate boiling,Film boiling,Critical heat flux,Minimum heat flux,nanofluids}, url = {https://scientiairanica.sharif.edu/article_22294.html}, eprint = {https://scientiairanica.sharif.edu/article_22294_57b8396995f979ef73272962e28e53ba.pdf} } @article { author = {Panda, S.K. and Mishra, P.K. and Panda, S.K.}, title = {Damage Propagation Prediction of Adhesion Failure in Composite T-joint Structure and Improvement using PZT Patch}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3232-3245}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.57083.5064}, abstract = {In this paper, a three dimensional finite element simulation model has been developed for the prediction, propagation and improvement of adhesion failure in an adhesively bonded laminated T-joint structure using the smart piezoelectric material. Initially, the three-dimensional stresses (normal and shear) and failure locations in the composite T-joint (all the layers of the web and flange) are evaluated. At the identified failure location, virtual crack closure technique (VCCT) of fracture mechanics has been employed to compute the strain energy release rate (SERR) values for different pre-embedded adhesion failure lengths. The developed coupling analysis model is used to evaluate the SERR responses for the laminated composite T-joint with single/multiple piezoelectric layers. The efficacy and improved performance (resistance to adhesion failure) of the laminated smart T-joint structure have been analysed in details by considering the different influencing parameters i.e. orientation schemes, material types, piezoelectric layers, thickness, number of layers of the laminate.}, keywords = {Adhesion failure,Piezoelectric material,Strain energy release rate,T-joint,Virtual crack closure technique}, url = {https://scientiairanica.sharif.edu/article_22275.html}, eprint = {https://scientiairanica.sharif.edu/article_22275_163bdc6679d54875676f88dfb91bd933.pdf} } @article { author = {Renuka Devi, R. L. V. and Siva Rama Raju, S.V. and Raju, C.S.K. and Shehzad, S. A. and Abbasi, F. M.}, title = {Hydromagnetic Blasius-Sakiadis flows with variable features and nonlinear chemical reaction}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3246-3258}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.54288.3681}, abstract = {Time-dependent, two-dimensional Sakiadis flow of quiescent fluid is considered. The flow is induced by stationary flat plate via uniform free-stream (Blasius flow). The variable conductivity and viscosity ratio parameters and non-linear chemical reaction are employed in the mathematical equations. Similarity variables are employed in the governing transport expressions to convert into the ordinary differential system. The transformed system is computed numerically by employing Runge-Kutta scheme via shooting criteria. Results of concentration, velocity and temperature distributions are studied through plots. Moreover, mass and heat transfer rates and friction factor have been discussed in detail. The constraint of chemical reaction slow down the friction-factors and heat transportation rates for the Sakiadis-Blasius flow situations and enhances the mass transportation rate in both cases. Rate of mass transportation is smaller in Sakiadis flow as comparative to Blasius flow. The present results of the heat transfer rate are matched with the literature and excellent agreement is noticed.}, keywords = {Viscous ratio parameter,non-uniform heat source-sink,variable conductivity,Blasius-Sakiadis flows,Chemical reaction}, url = {https://scientiairanica.sharif.edu/article_22341.html}, eprint = {https://scientiairanica.sharif.edu/article_22341_1322f227ec9b06b5c1d822aa54698897.pdf} } @article { author = {Shokrgozar Abbasi, A. and Najafian, M.}, title = {An experimental study of water freezing in cylindrical stagnation flow}, journal = {Scientia Iranica}, volume = {28}, number = {6}, pages = {3259-3271}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.57134.5082}, abstract = {In this experimental study, we investigate the freezing of water in cylindrical stagnation flow, using a device. The water impinges vertically on a cold flat plate while the water outlet section is cylindrical. The water starts to freeze when the substrate plate is sufficiently cold. The effects of distance between the outlet and the substrate plate, magnitude of the flow strain, water temperature, and the plate involved in ice formation, and most importantly, the final thickness of the ice have been investigated. We are also looking for a way to determine the flow regime in stagnation flow. Results are compared for validation with those of a numerical solution. The results show a good agreement in the middle of the ice thickness curve. As a result, the speed of ice formation is very high at first, and declines sharply with a steep slope. Also, a particular definition is employed for achieving the regimes (laminar, turbulent, or transitional) in stagnation flow. According to the results, the ice thickness in laminar flow is more than in turbulent one.}, keywords = {experimental investigation,Water Solidification,stagnation flow,Cylindrical freezing,Ice thickness}, url = {https://scientiairanica.sharif.edu/article_22257.html}, eprint = {https://scientiairanica.sharif.edu/article_22257_aa6e03a44490470c525cda7a9969e4b5.pdf} }