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Assessment of converting approach to efficient design of micro-turboprop engines

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Chinese Journal of Aeronautics 2020年第2期33卷 572-588页

作者： Hamed GOLCHIN fathollah ommi Zoheir SABOOHI Department of Mechanical Engineering Tarbiat Modares UniversityTehran 14115-111Iran Aerospace Research Institute(ARI) Ministry of ScienceResearchand TechnologyTehran 14115-111Iran

The design,manufacture and experiment of a shaft power unit for converting a microturbojet engine to a micro-turboprop in the class of less than 20 kW with the aim of obtaining maximum shaft power were described in this *** this purpose,a Wren 100 micro-turbojet engine was used as the gas generator,and the specifications of its outflow were *** optimal configuration of the inter-stage diffuser,which was an annular S-type diffuser,was selected based on its small total pressure drop and outlet flow *** power turbine was a single stage axial turbine that was designed based on the fixed nozzle angle assumption without any taper or twist in its *** turbine rotor was a bladed disk(Blisk)in which its unique blade profiles were designed based on the Wilson ***,the shaft power unit was completed by designing and manufacturing an exhaust complex and ***,the micro-turboprop engine was tested with an overloading *** results show a significant increase in the extracted power,an acceptable efficiency of the power turbine,and a significant reduction in the Specific Fuel Consumption(SFC)compared to other engines that use similar gas generators.

关键词： Axial turbine Blisk Gas generators Micro-turboprop Power unit

Effect of Oxygenates Blending with Gasoline to Improve Fuel Properties

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 792-796页

作者： BABAZADEH SHAYAN Soheil SEYEDPOUR Seyed Morteza ommi fathollah Department of Mechanical Engineering Tarbiat Modares UniversityTehranIran Department of Mechanical Engineering Iran University of Science and TechnologyTehranIran

The purpose of this paper is to study the effect of oxygenate additives into gasoline for the improvement of physicochemical properties of *** Tertiary Butyl Ether（MTBE）,Methanol,Tertiary butyl alcohol（TBA）,and Tertiary amyl alcohol（TAA） blend into unleaded gasoline with various blended rates of 2.5%,5%,7.5%,10%,15%,and 20%.Physicochemical properties of blends are analyzed by the standard American Society of Testing and Materials（ASTM） ***,TBA,and TAA increase density of the mixtures,but MTBE decreases *** addition of oxygenates lead to a distortion of the base gasoline＇s distillation *** Reid vapor pressure（RVP） of gasoline is found to increase with the addition of the oxygenated *** oxygenates improve both motor and research octane *** these four additives,TBA shows the best fuel properties.

关键词： gasoline oxygenates distillation curve reid vapor pressure octane number

Exergy Analysis of Charge and Discharge Processes of Thermal Energy Storage System with Various Phase Change Materials:A Comprehensive Comparison

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Journal of Thermal Science 2024年第2期33卷 509-521页

作者： Mojtaba TAHERI fathollah POURFAYAZ Roghayeh HABIBI Akbar MALEKI Department of Renewable Energies and Environment Faculty of New Sciences and TechnologiesUniversity of TehranTehran***Iran Faculty of Mechanical Engineering Shahrood University of TechnologyShahrood***Iran

Thermal energy storage(TES) is of great importance in solving the mismatch between energy production and *** this regard,choosing type of Phase Change Materials(PCMs) which are widely used to control heat in latent thermal energy storage systems,plays a vital role as a means of TES ***,this field suffers from lack of a comprehensive investigation on the impact of various PCMs in terms of *** address this issue,in this study,in addition to indicating the melting temperature and latent heat of various PCMs,the exergy destruction and exergy efficiency of each material are estimated and compared with each ***,in the present work the impact of PCMs mass and ambient temperature on the exergy efficiency is *** results proved that higher latent heat does not necessarily lead to higher exergy ***,to obtain a suitable exergy efficiency,the specific heat capacity and melting temperature of the PCMs must also be *** to the results,LiF-CaF_(2)(80.5%:19.5%,mass ratio) mixture led to better performance with satisfactory exergy efficiency(98.84%) and notably lower required mass compared to other ***,the highest and lowest exergy destruction are belonged to GR25 and LiF-CaF_(2)(80.5:19.5) mixture,respectively.

关键词： exergy analysis phase change materials thermal energy storage exergy efficiency

Spatially resolved investigation of flame particle interaction in a two dimensional model packed bed

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Particuology 2024年第2期85卷 167-185页

作者： Mohammadhassan Khodsiani Reza Namdar fathollah Varnik Frank Beyrau Benoit Fond Institute of Fluid Dynamics and Thermodynamics Universitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany Interdisciplinary Centre for Advanced Materials Simulation(ICAMS) Ruhr-University BochumBochum44801Germany ONERA The French Aerospace Lab Department of AerodynamicsAeroelasticity and Acoustics(DAAA)Paris-Saclay UniversityMeudon92190France

This study investigates the interaction between a premixed methane-air flame and particles inside a model packed *** opacity of the spherical packed beds to visible light poses a major barrier to the implementation of highly resolved optical diagnostics,so that no detailed experimental data were so far available for the validation of numerical ***,a two-dimensional cylindrical packed bed design is set up,which enables direct line-of-sight optical measurements without loss of spatial reso-lution over the fluid region between the *** this study,the case of cold metallic cylindrical particles(T=377 K)relevant to start-up of a reactor is investigated using internal particle cooling,which also allows cylinder specific heat transfer rate measurements by differential temperature measurements on the coolant *** two dimensional assumption is first verified by measuring the inflow ve-locity and cylinder temperature profile along the *** imaging is then per-formed using a telecentric lens to observe the position and geometry of the two-dimensional flame front with respect to the surrounding cylinders without loss of ***,the cylinder-specific flame to cylinder heat transfer rates and cylinder surface temperature are *** the flame is closely surrounded by the three cooled cylinders,intense heat transfer is observed in this region corresponding to 25±2.5%of the flame thermal *** were stabilised at different positions depending on inflow velocity and equivalence ratio,and a direct correlation between flame to cylinder stand-off distance and the heat transfer rate normalised to the flame thermal power was found for both top and side ***,sidewall quenching distances to the curved cylinder surfaces were evaluated,and seem to be influenced by the presence of a warm recirculation zone behind the *** investigation provides fully resolved flame front position and heat tra

关键词： Packed beds Flame-particle interaction Optical diagnostics Sidewall quenching

Numerical study of convective heat transfer in static arrangements of particles with arbitrary shapes:A monolithic hybrid lattice Boltzmann-finite difference-phase field solver

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Particuology 2024年第2期85卷 186-197页

作者： Reza Namdar Mohammadhassan Khodsiani Hesameddin Safari Tanya Neeraj Seyed Ali Hosseini Frank Beyrau Benoit Fond Dominique Thevenin fathollah Varnik Interdisciplinary Centre for Advanced Materials Simulation(ICAMS) Ruhr-University BochumBochum44801Germany Laboratory of Technical Thermodynamics University of Magdeburg"Otto von Guericke"Magdeburg39106Germany Laboratory of Fluid Dynamics and Technical Flows University of Magdeburg"Otto von Guericke"MagdeburgD-39106Germany Department of Mechanical and Process Engineering ETH ZurichZurich8092Switzerland ONERA The French Aerospace Lab Department of AerodynamicsAeroelasticity and Acoustics(DAAA)Paris-Saclay UniversityMeudon92190France

A compressible lattice Boltzmann-finite difference method is extended by the phase-field approach into a monolithic scheme to study fluid flow and heat transfer through regular arrangements of solid bodies of circular,elliptical and irregular *** advantage of using the phase-field method is demon-strated both in its simplicity of accounting for flow and thermal boundary conditions at solid surfaces with irregular shapes and in the capability of generating such complex-shaped *** an array of discs,numerical results for the overall solid-to-gas heat transfer rate are validated via experiments on flow through arrays of hot *** thus validated compressible LB-FD-PF hybrid scheme is used to study the dependence of heat transfer on flow and thermal boundary conditions(Reynolds number,temperature difference between the hot solid bodies and the inlet gas),porosity as well as on the shape of solid *** are rationalized in terms of the residence time of the gas close to the solid body and downstream variations of gas velocity and *** for further applications of the proposed methodology are also discussed.

关键词： Lattice Boltzmann method Finite difference scheme Convective heat transfer Diffuse interface Thermal compressible flow

Evaluating the effect of montelukast tablets on respiratory complications in patients following blunt chest wall trauma:A double-blind,randomized clinical trial

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Chinese Journal of Traumatology 2023年第2期26卷 116-120页

作者： Soleyman Heydari Hadi Khoshmohabat Ali Taheri Akerdi fathollah Ahmadpour Shahram Paydar Department of Surgery Baqiyatallah University of Medical SciencesTehranIran Trauma Research Center Baqiyatallah University of Medical SciencesTehranIran Trauma Research Center Shahid Rajaee(Emtiaz)Trauma HospitalShiraz University of Medical SciencesShirazIran

Purpose:Patients with multiple traumas are at high risk of developing respiratory complications,including pneumonia and acute respiratory distress *** pulmonary complications are associated with systemic inflammation and pulmonary neutrophilic ***-receptor antagonists are anti-inflammatory and anti-oxidant drugs subsiding airway *** present study investigates the effectiveness of montelukast in reducing pulmonary complications among trauma ***:This randomized,double-blind,placebo-control trial was conducted in patients with multiple blunt traumas and evidence of lung contusion detected via CT *** excluded patients if they met at least one of the following conditions: 0.05).At the end of the study,the mean (SD) of pulmonary contusion volume (mm3) (right side = 116748.74 (361705.12),left side = 64522.03 (117266.17)) of the treatment group were comparable to that of the placebo group (right side = 40051.26 (64081.56),left side = 25929.12 (47417.13),p = 0.228 and 0.082,respectively).Moreo

关键词： Acute respiratory distress syndrome Montelukast Leukotrienes Contusions Injuries

Exergetic sustainability evaluation and optimization of an irreversible Brayton cycle performance

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Frontiers in Energy 2019年第2期13卷 399-410页

作者： Mohammad H. AHMADI Mohammad-Ali AHMADI Esmaeil ABOUKAZEMPOUR Lavinia GROSU fathollah POURFAYAZ Mokhtar BIDI Renewable Energies Faculty of New Sciences and Technologies University of Tehran Tehran *** Iran Department of Petroleum Engineering Ahwaz Faculty of Petroleum Engineering Petroleum University of Technology (PUT) Ahwaz 61963165 Iran Graduate School of the Environment and Energy Science and Research Branch Islamic Azad University Tehran *** Iran University of Paris Ouest Nanterre La Defense 50 rue Sevres 92 410 Ville dAvray France Faculty of Mechanical & Energy Engineering Shahid Beheshti University A.C.Tehran ***Iran

Owing to the energy demands and global warming issue, employing more effective power cycles has become a responsibility. This paper presents a thermo-dynamical study of an irreversible Brayton cycle with the aim of optimizing the performance of the Brayton cycle. Moreover, four different schemes in the process of multi-objective optimization were suggested, and the outcomes of each scheme are assessed separately. The power output, the concepts of entropy generation, the energy, the exergy output, and the exergy efficiencies for the irreversible Brayton cycle are considered in the analysis. In the first scheme, in order to maximize the exergy output, the ecological function and the ecological coefficient of performance, a multi-objective optimization algorithm (MOEA) is used. In the second scheme, three objective functions including the exergetic performance criteria, the ecological coefficient of performance, and the ecological function are maximized at the same time by employing MOEA. In the third scenario, in order to maximize the exergy output, the exergetic performance criteria and the ecological coefficient of performance, a MOEA is performed. In the last scheme, three objective functions containing the exergetic performance criteria, the ecologi-cal coefficient of performance, and the exergy-based ecological function are maximized at the same time by employing multi-objective optimization algorithms. All the strategies are implemented via multi-objective evolu-tionary algorithms based on the NSGAII method. Finally, to govern the final outcome in each scheme, three well- known decision makers were employed.

关键词： entropy generation exergy Brayton cycle ecological function irreversibility

An Efficient Numerical Method and Parametric Study for Electrolyte Transport in the Renal Medulla

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Journal of Biomedical Science and Engineering 2014年第9期7卷 682-697页

作者： Maryam Saadatmand Mohammad J. Abdekhodaie Mahmoud R. Pishvaie fathollah Farhadi Department of Chemical and Petroleum Engineering Sharif University of Technology Tehran Iran

Mathematical models of the mamalian urine concentrating mechanism consist of a large system of coupled, nonlinear and stiff equations. An efficient numerical orthogonal collocation method was employed to solve the steady-state formulation of urine concentrating mechanism. This method was used to solve the stiff and high order equations of electrolyte transport in a central core, single nephron model of the renal outer medulla. The presented results were in good agreement with implicit finite difference method’s results, but this new method was faster and more stable. Due to the greater stability and larger convergence domain of collocation method over Newton’s method, a parametric study on concentrated urine was investigated. The results showed that this model was sensitive to non-ideal countercurrent exchange between medulla interstitium and vasa recta. Although distal tubule lies in the cortex interstitium, it affects on the inflow to the collecting duct. This study showed that the effect of changing membrane transport properties of distal tubule wall on properties of outflow from the outer medulla collecting duct was considerable.

关键词： Urine Concentrating Mechanism Central Core Model Electrolyte Transport Orthogonal Collocation Parametric Study

Strength Development of Cement-Slag Mortars

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Journal of Civil Engineering and Architecture 2012年第9期6卷 1169-1183页

作者： fathollah Sajedi Department of Civil Engineering Islamic Azad University- Ahvaz Branch Iran

In this experimental work, three groups of cement-slag mortars namely OPC, OPC-slag, and slag mortars were made. All were cured in both water and air under room temperature. Strength development was studied up to 90 days. The mortars were prepared using 0%, 50%, and 100% replacement with slag. The sensitivity for all groups was obtained against the curing regime with the highest being attributed to the slag mortars. The highest and lowest strengths at early ages were attributed to OPC and slag mortars when both were cured in water. The highest and lowest strengths were attributed to OPC-slag and slag mortars at later ages, respectively. The highest strengths for OPC-slag, OPC, and slag mortars were as 72.0, 64.0, and 21.5 MPa at 90 days when the specimens cured in water, respectively. Strength loss was observed for all groups at later ages when cured in air under room temperature. The maximum and minimum, of about 8.0% and 1.3%, occurred at 56 and 90 days for slag and OPC-slag mortars, respectively.

关键词：水泥砂浆矿渣砂浆砂浆强度 OPC 迫击炮强度损失试验性治愈