حاجی علی محمدی, علیرضا
دانشگاه سمنان
[ 1 ] - مطالعه عددی اثر محیط متخلخل بر ویژگی‌های فواره فشار قوی سوخت دیزل
در دهه اخیر ابتکار استفاده از محیط متخلخل در موتورهای احتراق داخلی جهت همگن کردن فرایند احتراق و کاهش سطح آلایندگی این موتورها، ارائه شده است. هدف از این پژوهش، بررسی مشخصه های کلان فواره سوخت دیزل در اثر برهم کنش با محیط متخلخل می باشد. میزان نفوذ فواره در دو حالت فواره آزاد و با حضور محیط متخلخل درون یک محفظه حجم ثابت و در فشارهای مختلف محفظه، با روش عددی بدست آمده و با نتایج تجربی موجود در ا...
[ 2 ] - شبیه سازی فرآیند تولید تزریق پودر فلزی با استفاده از نرم افزار Moldflow
فرآیند تولید تزریق پودر فلزی یکی از فرآیندهای جدید تولید قطعات دقیق و نزدیک به شکل نهایی می باشد که مکانیزم آن بر پایه روش متالورژی پودر می باشد. در این روش پودر فلزات به همراه چسب به داخل قالب تزریق می شوند و با توجه به سیالیت بیشتر مخلوط تشکیل شده در این حالت نسبت به روش متالورژی پودر، هندسه قطعات پیچیده تری را می توان به کمک آن تولید نمود. در بسیاری از صنایع از قبیل صنایع هوافضا، پزشکی و خود...
[ 3 ] - Experimental study of the diesel injector nozzle sediment effect on fuel spray behavior
High pressure amount of fuel in new generation diesel engines’ injector equipped with multiple and small nozzle holes has created significant improvement in the outgoing spray behavior and engine performance. On the other hand, poor fuel quality and injector nozzle embedded in high temperature combustion chamber form fundamental deposits on the nozzle leading to fuel spray inappropriate behavio...
[ 4 ] - Effects of Ageing and Forging on Short-term Creep Behaviors of Inconel-713C Superalloy at 850 °C
In this paper, the short-term creep behavior of the Inconel-713C superalloy after different pre-treatments including the ageing and forging processes has been studied at 850 °C. The ageing heat treatment was heating at 930 °C for 16 hours without solutioning process. The optical microscopy (OM) and the scanning electron microscopy (SEM) techniques were applied for microstructural evaluations. T...
[ 5 ] - Cutting Forces and Tool Wear Investigation for Face Milling of Bimetallic Composite Parts Made of Aluminum and Cast Iron Alloys
Bimetallic parts are used in many industries for weight and cost reduction of workpieces working under high loads and wear. One application for this type of composite material is in automotive industry. In this work the tool wear and cutting forces in the face milling of bimetallic parts made of aluminum and cast iron were investigated. A356 and GG25 alloys that are common materials for bimetal...
[ 6 ] - Investigating of Process Design Parameters in 4043 alloy Additive Manufactured specimens, to create external features of cylinder head
In Wire and Arc Additive Manufacturing (WAAM), a 3D object is created from small material sectors,. It usually adds layers of material continuously to produce the final shape. The challenges facing additive manufacturing methods for functional or mass production parts, are still complex geometries, used materials, quality of manufactured components, cycle time and cost. The solubility of hydrog...
[ 7 ] - Numerical and experimental investigation of common rail fuel injection system and evaluating influence of fuel pressure on injection characteristics and pressure fluctuations
The combustion processes, engine performance, fuel consumption, exhaust-gas composition, and combustion noise in the diesel engine are closely linked to appropriate mixture of air-fuel in combustion chamber. The fuel-injection parameters such as injection start point, discharge rate curve, injection time and injection pressure are defined by the quality of the mixture formation. The numerical m...