• فهرست مطالب:

 چکیده
۱ مقدمه
۲ کار تجربی
۳ نتایج و بحث
۴ ملاحظات پایانی

• بخشی از ترجمه:

1-لوله شوك آيروسل با اتصال به پيستون براي پركردن آيروسل توسعه يافته است. آيروسل قبلا مخلوط شده و اندازه دانه اي در حدود 3μm دارد.
2-تاخير اشتعال نفت سفيد، مخلوط تجزيه شده در لوله هاي شوك بدست امده است. اين مخلوط هوا است و همچنين مخلوطي از سوخت و اكسيژن و آرگون مي باشدذ.
3-تاخير در احتراق وابسته به فشار و نسبت هم ارزي بدست امده به طوري كه مقايسه مي تواند براي داده هاي مختلف از قبيل فشار ، نسبت تعادل، اندازه شوك، در شرايط آزمون هاي مختلف بدست آيد.

• بخشی از مقاله انگلیسی:

. Introduction For combustion studies of scramjet and detonation, ignition delay of kerosene and its cracked mixture are important for combustor design. Also, in calibration of fuel chemistry elementary reaction models, ignition delay is used to judge chain reaction steps. Usually, shock tube is almost a unique facility to obtain delay of auto-ignition. In fact, industrial fuels are almost liquid, so, how to get liquid fuel ignition delay in shock tubes is still a challenge topic at present. Davison and Hanson[1] used ultrasonic nebulizer to produce kerosene aerosol in mixture of Argon and oxygen and got ignition delay for liquid fuels. Hydraulic assembly connected to shock tube end is used to inlet aerosol. In this paper, premixed kerosene aerosol in air mixture is formed outside shock tube and an aerosol shock tube is developed with piston assembly at reflection end for aerosol inlet. A tube with large inner and bend diameters are used to avoid droplets adsorption collision to tube walls during filling. In this shock tube, kerosene and its cracked mixture[2]are studied for obtaining ignition delay. 2.Experiments Fig 1 presents a schematic of set-up for aerosol forming. Tank is vaccumed and kerosene is sucked by a fuel nozzle at diameter 0.3mm in throat of Laval nozzle with constant throat. Air is inlet from a gas bottle at specified pressure by a regular meter. Equivalent ratio is predetermined by air mass in tank and metered volume of kerosene. Fig 2 shows schematic of gas distributor for shock tube. Sections of high pressure(1), low pressure(3) and diaphragm(2) are conventional. But piston setup is attached to reflection end. Fig 3 presents picture and schematic of piston setup. When aerosol is filled into low pressure section, piston is opened and entered aerosol is vaccumed initially so that inner tube walls can be wetted. Then, piston is closed and aerosol filling is finished at specified pressure. By Mie scattering, SMD of droplet is ranged from 3μm to 4.5μm at tank pressure from 0.14MPa to 1.8MPa(Fig 4). No kerosene is condensed on quartz windows in shock tube test section due to low pressure. Fig 5 shows how to determine ignition delay by signal time histories of pressure gas and photomultiplier(PMT). Dispersed burning zones occur randomly in test section at low temperature. Therefore, it is difficult to determine auto-ignition delay because of several peaks of light signal(Fig 6). In our experiments, we neglect such paradox conditions and minimum temperature is found when unique peak appears in PMT signal(fig 5). 3 Results and Discussions Fig 7 and Fig 8 present ignition delay at different temperature and pressure. In Fig 7, ignition delays are in agreement with precious data but different at low temperature. Ignition delay is obtained in shock tube with heat tape in low pressure section. Complex decomposition and fractionation possibly occur while heating. In Fig 8, ignition delay is decreased when pressure is increased for the same temperature.

نوشته دانلود ترجمه مقاله تاخیر در خود اشتعالی نفت سفید آیروسل و مخلوط آن با مطالعه شوک لوله – مجله الزویر اولین بار در ترجمه فا پدیدار شد.

• فهرست مطالب:

چکیده
مقدمه
مدلسازی CFD
شبیه سازی ثابت
جریان در حلقه
جریان در روتور
شبیه سازی ناپایدار
تجزیه و تحلیل طیفی
شبیه سازی جریان ضربانی
نتیجه گیری

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شبيه سازي جريان پايدار و گذرا از طريق اجزاي توربين شعاعي با دو ورودي ، بينش خوبي نسبت  با ساختارهاي پيچيده جريان  هوا را بوجود مي اورد. در مرحله اول، نفوذ زبانه توسط فاشر كم از سيال ورودي  به روتور با زاويه  600   به تصوير كشيده شده است. در مرحله دوم منطقه بين فضا توسط تلفات ، با توجه به اختلاط مشخص بين جريان كفي و توپي در تقسيم جريان وجود دارد. تجزيه و تحليل طيفي نوسانات فشار در دوره تناوبي فضاي زمان براي مورد شبيه سازي گذرا، هردو حالبت جريان ضربان دار و غير ضربان دار در ورودي نشان داده شده است. همچنين حالت  فضا و سرعت چرخشي و دامنه مشخص اين ناپايداري ها تعيين مي شود. پره و تعاملات روتور به وضوح از طريق شرايط روتور و زبانه و اثرات بالقوه  ارائه شده است. در مورد تجزيه و تحليل جريان ضربان دار مي توان گفت كه تسلط بر فركانس پالس زماني بوده و تقسيم عددي بر مضرب BPF بوده و تعامل  بين زبان ه وپره به نظر مي رسد كه غالبتر است. براي پذيرش نابرابري مختلف، تجزيه و تحليل طيفي نوسانات  فشار در درون فضا ثبت شده كه به نظر مي رسد همان رفتار از سيگنال هاي فضايي بدست امده از طريق ارتباط ثابت n مي باشد.  

• بخشی از مقاله انگلیسی:

Introduction Radial inflow turbines are widely used in the turbocharging of diesel engines owing to their capacity to absorb the residual energy from exhaust gases. For a single-entry volute, the flow rate of exhaust gas is low at lower engine speeds, and therefore the exhaust pressure at the gathering point of an exhaust manifold is low, resulting in a low boost pressure. By using a twin-entry radial inflow turbines there is a better recovery of energy from the pulsating exhaust gases. Despite they become extensively used in turbocharging, they only benefited from few studies as compared to single-entry radial turbines. Pischiger and Wunsche1 studied twin-entry turbines under steady conditions and showed that unequal inlet conditions have a significant effect on the turbine performance. Also, Dale and Watson2 indicated significant effects of partial and unequal admissions on both the swallowing capacity and efficiency of a twin-entry turbine, and showed that the maximum efficiency does not necessarily occur under equal admission, and these conclusions were also supported by the experiments of Capobianco and Gambarotta.3 Yeo and Baines4,5 extended the study of Dale and Watson using laser two-focus velocimetry techniques to examine the flow inside a turbine, and showed that for different operating points and equal admission the flow incidence is close to 30. Doppler velocimetry measurements by Karamanis et al.6 under steady and pulsating conditions revealed complex flow patterns at both inlet and exit and the unsteady performance have a substantial deviation from the performance and flow characteristics of steady state. Experimental results of two versions of a mixed-flow turbine were obtained by Hakeem et al.,7 which revealed that in the steady case, the use of a volute with a larger swallowing capacity may result in a higher isentropic efficiency at lower speeds and higher velocity ratios, whereas the unsteady case indicated that the instantaneous performance and flow characteristics deviate substantially from their steady-state values. In the last two decades, the flow simulations in the support of turbomachinery design and development have grown to a considerable extent, as a consequence of the rapid evolution of computing power. By using CFX code, Simpson et al.8,9 showed that the vaned stators present a higher total pressure losses compared to equivalent vaneless volutes which exhibit higher levels of flow uniformity at rotor entry, yielding an improved turbine efficiency, which was also confirmed by the experimental investigations due Spence et al.10 The performance of a turbocharger’s twin-entry radial turbine was investigated analytically and experimentally by Aghaali and Hajilouy-Benisi11 and Hajilouy-Benisi et al.12 under steady state, considering the full and partial admission. The results revealed that when the ratio of the shroud and hub side mass flows is very high, the efficiency is lower than that of the full admission. Hellstro¨m and Fuchs,13 in their first report presented numerical analyses for a vaneless turbine coupled to an IC engine operating at 1500 r/min and 3000 r/min, concluded that for the second speed, the inlet flow angle varies from approximately from 67 to 25 which is more favourable than for the first speed where this angle was from 85 to 60 accompanied with a drop in the peak shaft power about 4%. In their two other reports,14,15 a variety of non-pulsatile inlet boundary conditions including uniform flow and several combinations of turbulence with swirl and streamwise vortices were tested. As results, the undisturbed inlet profile gave the highest time-averaged power output while the performance of pulsating flow deviates subsequently from the steady one, as also confirmed later by Costall et al.,16 Copeland et al.17 Romagnoli et al.18 compared between the steady performance of double-entry and twin-entry turbocharger turbines, and showed that in the case of a twin radial turbine, the interaction between entries is significant and causes the flow capacity to be larger than that would be obtained by halving the mass flow in a full admission in contrary to the double-entry turbine. The interaction phenomena between the rotor and the stationary components is considered to have a strong influence on the flow of a radial turbine and a better understanding is required in order to improve its design.

نوشته دانلود ترجمه مقاله آنالیز جریان ثابت و ناپایدار در توربین شعاعی موتور شارژ کننده توربین اولین بار در ترجمه فا پدیدار شد.