scholarly journals Identification of emission indicators harmful compounds for assessment of dynamic state of a marine diesel engine

2019 ◽  
Vol 178 (3) ◽  
pp. 247-251
Author(s):  
Artur BOGDANOWICZ ◽  
Ryszard ZADRĄG
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Propulsion System ◽  
Dynamic State ◽  
Marine Diesel Engine ◽  
Single Base ◽  
Marine Diesel ◽  
Engine Dynamic ◽  
Dynamic States ◽  
State Analysis

The operation of a ships propulsion system is a variable process in time, which is described in both static and dynamic states. The mutual proportions between them depend primarily on a type of ship and tasks to which it was designed. In a case of special units of particular use (e.g. warships) and ships, which operate on narrow waters such as canals or port basins, participation of dynamic states is increasing significantly. Hence a necessity to analyze the dynamic states of marine diesel engines, among others in terms of their increased harmful compounds emission. The paper presents a methodology of engine dynamic state analysis, emission indicators that can be used to assess the dynamic state of a ship have been proposed. As an example of application, the analysis of harmful compounds emissions during dynamic states while a real cruise of navy ship has been carried out. It has been also proposed to use simple dynamics indicators such as single-base and chain indexes to describe the change in concentrations of harmful compounds in dynamic states.

Numerical investigation of interaction between propulsion system behaviour and manoeuvrability of a large containership

2021 ◽  
pp. 147509022110442
Author(s):  
Huan Tu ◽  
Hui Chen
Keyword(s):  
Diesel Engine ◽  
Coupled Model ◽  
Propulsion System ◽  
Marine Diesel Engine ◽  
Large Power ◽  
Engine Model ◽  
Ship Manoeuvring ◽  
System Behaviour ◽  
Marine Diesel ◽  
Actual Operation

In actual operation process of a ship, the engine-propeller-hull is an integrated system with internal coupling effects, and thus there is a close interaction between the diesel engine propulsion system operation conditions and the ship manoeuvring motions. The propulsion system can experience large power fluctuation during manoeuvring, with considerable torque increase with regard to the stabilized value in straight course. However, the diesel engine propulsion system behaviour and ship manoeuvrability are usually studied separately as they are considered to belong to different disciplines. Thus, it is difficult to reflect the actual operating characteristics of the propulsion system and ship manoeuvring motion under coupled conditions in actual operation. To investigate the interaction between the propulsion system behaviour and the manoeuvrability of a large containership, this paper proposed a multi-disciplinary ship mobility model capable of coupling the marine diesel engine model and the ship manoeuvring model. In the engine model, the mean value modelling approach was adopted to simulate the two-stroke marine diesel engine considering the fact that it can capture the performance of the engine sub-systems including scavenging receiver, exhaust gas receiver, turbocharger, etc. In the manoeuvring model, the MMG-based method was used to simulate the ship manoeuvring motion with three degrees-of-freedom. The engine model and manoeuvring model were coupled through the propeller model that transferring propeller speed and torque between the two models. The coupled model was validated against the engine shop test data and the sea trial results. By applying this coupled model, a series of simulations of turning circle manoeuvres under various scenarios were performed. The simulation results presented the dynamic response of engine internal sub-systems during turning circle manoeuvring, explained the effect of the torque limiter on engine performance and ship manoeuvring motion, and analyse the influence of different propulsion system control strategies on the ship turning circle manoeuvrability. Although the presented case study has been validated on a specific ship, most of the discussed models have a general application.

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.

scholarly journals Dynamics of marine diesels when using motor oils with different structural characteristics

2021 ◽  
Vol 27 (1) ◽  
pp. 108-119
Author(s):  
Сергей Викторович Сагин ◽  
Тимур Александрович Столярик
Keyword(s):  
Molecular Structure ◽  
Boundary Layer ◽  
Steady State ◽  
Diesel Engine ◽  
Diesel Engines ◽  
Structural Characteristics ◽  
Marine Diesel Engine ◽  
Marine Engine ◽  
Lubricating Layer ◽  
Marine Diesel

Annotation – The influence of the structural characteristics of engine lube oil on the dynamics of a marine diesel engine is considered. It is indicated that micron layers of marine engine lube oils separating the contact surfaces of marine diesel engines acquire the properties of liquid crystals and are characterized by an ordered molecular structure. The qualitative indicator of this structure is the degree of ordering of the molecules, and the quantitative indicator is the thickness of the ordered (boundary) lubricating layer. It is proposed to determine the structural characteristics of marine engine lube oils (the degree of ordering of the molecules of the boundary layer and its thickness) using the optical method of absorption dichroism. A diagram of an experimental setup is presented that allows such studies to be carried out. It has been experimentally established that for Shell Rimula X15 and Castrol TPL 123 engine lube oils (used in the oil system of the Caterpillar CatC18 marine diesel engine), the thickness of the ordered (boundary) lubricating layer is 14.3 ... 14.7 microns and 16.4 ... 16.6 microns, respectively. The degree of ordering of molecules in the boundary layer for Shell Rimula X15 engine lube oil is in the range of 0.56 ... 0.58, for Castrol TPL 123 engine lube oil – in the range of 0.63 ... 0.64. The results of studies of the dynamics of the CatC18 marine diesel engine by Caterpillar, carried out in the starting mode, as well as at various increases and decreases in load, are presented. As indicators, which were used to assess the dynamics of the diesel engine, the overshoot of the rotational speed and the time to reach a new steady state mode were taken. Experiments have confirmed that Castrol TPL 123 engine lube oil, which has a higher molecular structure in the boundary layer compared to Shell Rimula X15 lube oil, ensures the transient processes of the Caterpillar CatC18 marine diesel engine with less overspeed and less time to reach a new state work. The proposed technology for determining the structural characteristics of engine lube oils can be used for any type and grade of oil (mineral or synthetic, high and low viscosity, used both in circulating and cylinder lubrication systems). The proposed method for assessing the dynamic characteristics of marine diesel engines (by overshoot of the speed and the time to reach a steady state of operation in the event of a change in load) can be used for any types of internal combustion engines (low-, medium- and high-speed; as well as performing the functions of both main and auxiliary engines).

scholarly journals Numerical determination of the velocity fields of the working medium in the combustion chamber of a marine high-speed diesel engine

2020 ◽  
pp. 92-97
Author(s):  
Б.И. Руднев ◽  
О.В. Повалихина
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Combustion Chamber ◽  
Convective Heat ◽  
Diesel Engines ◽  
High Speed ◽  
Velocity Fields ◽  
Marine Diesel Engine ◽  
Working Medium ◽  
Marine Diesel

Современные тенденции развития судовых дизелей связаны, прежде всего с улучшением их энергетических и экологических характеристик. Это обуславливает появление ряда проблем, важнейшая из которых – возрастание теплонапряженности деталей, образующих камеру сгорания. Высокие локальные тепловые потоки на поверхностях крышки цилиндра, поршня и втулки являются одной из главных причин, снижающих эксплуатационную надежность форсированных судовых дизелей. Достоверность расчетной оценки теплового и напряженно-деформированного состояния деталей, образующих камеру сгорания, определяется главным образом правильностью задания локальных граничных условий со стороны рабочего тела. Учитывая, что доля конвективного теплового потока в суммарном теплообмене достигает в среднем за рабочий цикл 60 – 70%, становится очевидной актуальность разработки надежных расчетно-теоретических методов определения полей скоростей рабочего тела в камере сгорания судовых дизелей. Целью данной статьи является дальнейшее совершенствование математической модели локального конвективного теплообмена в камере сгорания высокооборотного судового дизеля. Показано, что внешнее течение рабочего тела в камере сгорания может быть описано уравнениями Эйлера. Представлены поля скоростей рабочего тела в функции угла поворота коленчатого вала, полученные численным методом. Приведены изотермы и изобары рабочего тела, позволяющие более глубоко проанализировать физику процесса конвективного теплообмена в камере сгорания судового высокооборотного дизельного двигателя. Modern trends in the development of marine diesel engines are associated primarily with the improvement of their energy and environmental characteristics. This gives rise to a number of problems, the most important of which is an increase in the combustion intensity. High local heat fluxes on the surfaces of the cylinder head, piston and liner are one of the main reasons that reduce the operational reliability of boosted marine diesel engines. The reliability of the calculated estimate of the thermal and stress-strain state of parts that form the combustion chamber is mainly determined by the correctness of setting the local boundary conditions from the part of the working medium. Taking into account that the share of convective heat flux in the total heat exchange reaches, on average, 60 - 70% for a working cycle, it becomes obvious the urgency of developing reliable computational and theoretical methods for determining the velocity fields of the working medium in the combustion chamber of marine diesel engines. The purpose of this article is to further improve the mathematical model of local convective heat transfer in the combustion chamber of a high-speed marine diesel engine. It is shown that the external flow of the working medium in the combustion chamber can be described by the Euler equations. The velocity fields of the working medium as a function of the angle of rotation of the crankshaft obtained by the numerical method are shown. Isotherms and isobars of the working medium are given, which allow a more in-depth analysis of the physics of the convective heat transfer process in the combustion chamber of a high-speed marine diesel engine.

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