scholarly journals Theoretical assessment of the stress-strain state of the cylinder sleeve of a marine diesel engine from the effects of variable moving gas loads

2021 ◽  
pp. 49-53
Author(s):  
Л.И. Ковальчук ◽  
М.В. Бураковская
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Strain State ◽  
Cylinder Block ◽  
Marine Diesel Engine ◽  
Stress Strain ◽  
Intermediate Support ◽  
Stress Strain State ◽  
Marine Diesel ◽  
Cylinder Sleeve

Цилиндровые втулки относятся к наиболее нагруженным деталям судовых дизелей. Оценка их напряженно-деформированного состояния показывает, что последовательное форсирование дизелей по среднему эффективному давлению требует существенного пересмотра некоторых положений конструирования этих деталей. Это касается конструктивного оформления наружных поверхностей втулок, а также их закрепления в блоке цилиндров. В статье рассматривается влияние условий закрепления верхнего торца втулки и промежуточных опор-уплотнителей на деформирование цилиндровой втулки газовыми нагрузками. Показано, что для выбора оптимального места установки кольца-уплотнителя по длине втулки целесообразно исходить из минимизации воздействий на него со стороны подвижных газовых нагрузок. Предлагается расчётная методика, которая позволяет определить то место установки промежуточной опоры, где она практически не влияет на параметры напряженно-деформированного состояния цилиндровой втулки судового дизеля с учётом особенностей закрепления её верхнего торца в цилиндровом блоке. Применение данной методики позволяет с учётом особенностей конкретного двигателя обоснованно решить вопрос размещения дополнительных опор-уплотнителей. Cylinder bushings are among the most loaded parts of marine diesel engines. Evaluation of their stress-strain state shows that the sequential forcing of diesel engines according to the average effective pressure requires a significant revision of some provisions for the design of these parts. This applies to the design of the outer surfaces of the bushings, as well as their fastening in the cylinder block. The article examines the influence of the conditions for fixing the upper end of the sleeve and intermediate support-seals on the deformation of the cylinder sleeve by gas loads. It is shown that in order to select the optimal place for installing the seal ring along the length of the sleeve, it is advisable to proceed from the minimization of the effects on it from the movable gas loads. A calculation method is proposed that allows you to determine the place of installation of the intermediate support, where it practically does not affect the parameters of the stress-strain state of the cylinder liner of a marine diesel engine, taking into account the peculiarities of fixing its upper end in the cylinder block. The use of this technique allows, taking into account the characteristics of a particular engine, to reasonably solve the issue of placing additional support-seals.

Computer aided study of the transient performances of a highly rated sequentially turbocharged marine diesel engine

1998 ◽  
Vol 212 (3) ◽  
pp. 185-196 ◽  
Author(s):  
X Tauzia ◽  
J F Hetet ◽  
P Chesse ◽  
G Crosshans ◽  
L Mouillard
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Diesel Engines ◽  
Marine Diesel Engine ◽  
Computer Aided ◽  
Compressor Surge ◽  
Marine Diesel ◽  
Valve Opening ◽  
Transient Phases ◽  
Good Agreement

The sequential turbocharging technique described in this paper leads to an improvement in the operations of highly rated diesel engines, in particular at part loads (better air admission). However, transient phases such as a switch from one turbocharger to two turbochargers can be difficult, mainly because of the inertia of the turbochargers. In order to simulate the dynamics of turbocharged diesel engines, the SELENDIA software has been extended. When applied to two different engines (12 and 16 cylinders), the program shows good agreement with the experimental data. Moreover, the compressor surge has been investigated during faulty switch processes. The software has then been used for predictive studies to evaluate the possibility of adapting sequential turbocharging to a 20-cylinder engine and to calibrate the optimum switching conditions (air and gas valve opening timing).

scholarly journals Computational and experimental determination of flame radiation parameters in the combustion chamber of a marine diesel engine

2020 ◽  
pp. 98-102
Author(s):  
Б.И. Руднев ◽  
О.В. Повалихина
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Combustion Chamber ◽  
Experimental Method ◽  
Diesel Engines ◽  
Flame Temperature ◽  
Marine Diesel Engine ◽  
Gas Temperature ◽  
Flame Radiation ◽  
Marine Diesel

Температура пламени и степень черноты определяют его собственное излучение. Однако оценка указанных параметров на стадии проектирования судовых дизелей представляет собой трудную и еще пока нерешенную проблему. Последнее обусловливается сложностью достоверного математического моделирования процесса сгорания топлива в дизельных двигателях и весьма высокой стоимостью экспериментальных исследований в этой области. Целью данной статьи является разработка расчетно-экспериментального метода определения параметров излучения пламени в камере сгорания судового дизеля 6 ЧН 24/36. Показано, что оценка величины температуры пламени в камере сгорания в функции угла поворота коленчатого вала может быть выполнена по температуре газов, найденной из экспериментальной или расчетной индикаторной диаграммы и специального параметра. Последний определяется на основании зависимости, полученной путем обобщения экспериментальных данных по измерениям температуры пламени на ряде дизельных двигателей. Представлены результаты по температуре пламени для судового дизеля 6 ЧН 24/36, полученные с использованием разработанного расчетно-экспериментального метода. Установлено, что с ростом нагрузки температура пламени возрастает. При этом в диапазоне изменения нагрузки дизеля от 50% до 100% от номинальной мощности увеличение температуры пламени примерно в два раза превышает увеличение температуры газов. Использование полученных результатов для оценки собственных потоков излучения пламени в камере сгорания судового дизеля 6 ЧН 24/36 и сопоставление их с известными экспериментальными данными показало сходимость в пределах 10 – 15%. The flame temperature and radiating power are determined with its own radiation. However, the assessment of these parameters at the design stage of marine diesel engines is a complicated and still unsolved problem. The latter is due to the complexity of reliable mathematical modeling of the fuel combustion process in diesel engines and the very high cost of experimental research in this area. The purpose of this article is to develop a computational and experimental method for determining the parameters of flame radiation in the combustion chamber of marine diesel engine 6 ChN 24/36. It is shown that the estimation of the value of flame temperature in the combustion chamber as a function of the crankshaft rotation angle can be performed using the gas temperature found from the experimental or calculated indicator diagram and a special parameter. The latter is determined on the basis of the dependence obtained by generalizing experimental data of the flame temperature measurements at a number of diesel engines. The results on the flame temperature for marine diesel engine 6 ChN 24/36, obtained using the developed computational and experimental method, are presented. It has been found that the flame temperature increases with increasing load. At the same time, in the range of diesel load variation from 50% to 100% of the nominal power, an increase in the flame temperature is approximately twice more than an increase in the gas temperature. The use of the results obtained to assess the intrinsic fluxes of flame radiation in the combustion chamber of marine diesel engine 6 ChN 24/36 and their comparison with the known experimental data showed the convergence within 10 - 15%.

An Experimental Study on Fuel Economy Improvement of a Marine Diesel Engine Using a Sequential Turbocharging System

2018 ◽  
Author(s):  
Hechun Wang ◽  
Xiannan Li ◽  
Yinyan Wang ◽  
Hailin Li
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Diesel Engines ◽  
Engine Speed ◽  
Single Stage ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Engine Operation ◽  
Marine Diesel ◽  
High Torque

Marine diesel engines usually operate on a highly boosted intake pressure. The reciprocating feature of diesel engines and the continuous flow operation characteristics of the turbocharger (TC) make the matching between the turbocharger and diesel engine very challenging. Sequential turbocharging (STC) technology is recognized as an effective approach in improving the fuel economy and exhaust emissions especially at low speed and high torque when a single stage turbocharger is not able to boost the intake air to the pressure needed. The application of STC technology also extends engine operation toward a wider range than that using a single-stage turbocharger. This research experimentally investigated the potential of a STC system in improving the performance of a TBD234V12 model marine diesel engine originally designed to operate on a single-stage turbocharger. The STC system examined consisted of a small (S) turbocharger and a large (L) turbocharger which were installed in parallel. Such a system can operate on three boosting modes noted as 1TC-S, 1TC-L and 2TC. A rule-based control algorithm was developed to smoothly switch the STC operation mode using engine speed and load as references. The potential of the STC system in improving the performance of this engine was experimentally examined over a wide range of engine speed and load. When operated at the standard propeller propulsion cycle, the application of the STC system reduced the brake specific fuel consumption (BSFC) by 3.12% averagely. The average of the exhaust temperature before turbine was decreased by 50°C. The soot and oxides of nitrogen (NOx) emissions were reduced respectively. The examination of the engine performance over an entire engine speed and torque range demonstrated the super performance of the STC system in extending the engine operation toward the high torque at low speed (900 to 1200 RPM) while further improving the fuel economy as expected. The engine maximum torque at 900 rpm was increased from 1680Nm to 2361 Nm (40.5%). The average BSFC over entire working area was improved by 7.4%. The BSFC at low load and high torque was significantly decreased. The application of the STC system also decreased the average NOx emissions by 31.5% when examined on the propeller propulsion cycle.

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