Study on the Operating Process of an Underwater Diesel Engine

2008 ◽  
Vol 52 (04) ◽  
pp. 239-248
Author(s):  
Yi Cui ◽  
Yilun Zhu ◽  
Kangyao Deng
Keyword(s):  
Diesel Engine ◽  
Froude Number ◽  
Sea Water ◽  
Research Work ◽  
Three Dimensional ◽  
Back Pressure ◽  
Water Flooding ◽  
Exhaust Gas ◽  
Two Phase ◽  
Tail Pipe

A steady state and transient simulation model for an underwater diesel engine system, including governor, diesel engine, and pipe systems after turbine, is developed and verified. A two-phase flow of exhaust gas and water at the tail pipe is studied with three-dimensional fluid dynamics calculation. A water flooding criterion for an underwater engine is also given by these models and related experiments. Safe operation ranges of the engine are also studied. The histories of relative engine speed, pressure, and Froude number of the tail pipe exhaust gas under starting and stopping processes are studied. The Froude number of the tail pipe exhaust gas is an oscillating phenomena when the engine is starting, which is likely to cause sea water to flow backward into the tail pipe. The opening of the tongue valve must be controlled according to engine back pressure during the stopping process to prevent sea water flooding on the one hand and high back pressure on the other. The underwater diesel engine operating control strategy can be given on the basis of the research work.

scholarly journals Wake behind a three-dimensional dry transom stern. Part 1. Flow structure and large-scale air entrainment

2019 ◽  
Vol 875 ◽  
pp. 854-883 ◽  
Author(s):  
Kelli Hendrickson ◽  
Gabriel D. Weymouth ◽  
Xiangming Yu ◽  
Dick K.-P. Yue
Keyword(s):  
Froude Number ◽  
Flow Structure ◽  
Large Scale ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Breaking Waves ◽  
Variable Density ◽  
Entrainment Rate ◽  
Two Phase ◽  
Density Spectrum

We present high-resolution implicit large eddy simulation (iLES) of the turbulent air-entraining flow in the wake of three-dimensional rectangular dry transom sterns with varying speeds and half-beam-to-draft ratios $B/D$. We employ two-phase (air/water), time-dependent simulations utilizing conservative volume-of-fluid (cVOF) and boundary data immersion (BDIM) methods to obtain the flow structure and large-scale air entrainment in the wake. We confirm that the convergent-corner-wave region that forms immediately aft of the stern wake is ballistic, thus predictable only by the speed and (rectangular) geometry of the ship. We show that the flow structure in the air–water mixed region contains a shear layer with a streamwise jet and secondary vortex structures due to the presence of the quasi-steady, three-dimensional breaking waves. We apply a Lagrangian cavity identification technique to quantify the air entrainment in the wake and show that the strongest entrainment is where wave breaking occurs. We identify an inverse dependence of the maximum average void fraction and total volume entrained with $B/D$. We determine that the average surface entrainment rate initially peaks at a location that scales with draft Froude number and that the normalized average air cavity density spectrum has a consistent value providing there is active air entrainment. A small parametric study of the rectangular geometry and stern speed establishes and confirms the scaling of the interface characteristics with draft Froude number and geometry. In Part 2 (Hendrikson & Yue, J. Fluid Mech., vol. 875, 2019, pp. 884–913) we examine the incompressible highly variable density turbulence characteristics and turbulence closure modelling.

Design and Development of Surge Tank for NOx Emission Reduction in B20 Biofueled Diesel Engine

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Jaspreet Hira ◽  
Basant Singh Sikarwar ◽  
Rohit Sharma ◽  
Vikas Kumar ◽  
Prakhar Sharma
Keyword(s):  
Diesel Engine ◽  
Research Work ◽  
Engine Performance ◽  
Nox Emission ◽  
Intake Manifold ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Surge Tank ◽  
Brake Thermal Efficiency ◽  
Exhaust Gas Temperature

In this research work, a surge tank is developed and utilised in the diesel engine for controlling the NOX emission. This surge tank acts as a damper for fluctuations caused by exhaust gases and also an intercooler in reducing the exhaust gas temperature into the diesel engine intake manifold. With the utilisation of the surge tank, the NOX emission level has been reduced to approximately 50%. The developed surge tank is proved to be effective in maintaining the circulation of water at appropriate temperatures. A trade-off has been established between the engine performance parameters including the brake thermal efficiency, brake specific fuel consumption, exhaust gas temperature and all emission parameters including HC and CO.

Modeling of the Onset of Gas Entrainment Through a Finite-Side Branch

2003 ◽  
Vol 125 (5) ◽  
pp. 902-909 ◽  
Author(s):  
M. Ahmed ◽  
I. Hassan ◽  
N. Esmail
Keyword(s):  
Froude Number ◽  
Three Dimensional ◽  
Phase Region ◽  
Side Branch ◽  
Critical Height ◽  
Two Phase ◽  
Gas Entrainment ◽  
Branch Model ◽  
Predicted Values ◽  
New Criterion

A theoretical investigation has been conducted for the prediction of the critical height at the onset of gas entrainment during single discharge from a stratified, two-phase region through a side branch with a finite diameter. Two different models have been developed, a simplified point-sink model and a three-dimensional finite-branch model. The two models are based on a new criterion for the onset of gas entrainment. The results of the predicted critical heights at the onset of gas entrainment showed that the finite-branch model approaches the physical limits at low Froude numbers. However, as the values of the Froude number increased, the predictions of both models eventually converged to the same value. Based on the results of the models, the critical height corresponding to the onset of gas entrainment was found to be a function of Froude number and fluid densities. The results of both models are compared with available experimental data. The comparisons illustrate a very good agreement between the measured and predicted values.

Experimental Investigations of Porosity, Diameter and Length of Ceramic Diesel Particulate Filter (DPF)

2009 ◽  
Author(s):  
Nishikant V. Deshpande ◽  
Suhas C. Kongre ◽  
Piyush N. Deshpande ◽  
Rajan Singh
Keyword(s):  
Particulate Matter ◽  
Diesel Engine ◽  
Power Plant ◽  
Thermal Efficiency ◽  
Research Work ◽  
Back Pressure ◽  
Diesel Particulate ◽  
Brake Thermal Efficiency ◽  
Particulate Filters ◽  
Brake Power

Diesel engine is the most efficient power plant among all known types of internal combustion engines. The Diesel engine is a major candidate to become the power plant of the future. Environmental benefits of Diesel such as low green house gas emissions are balanced by growing concern with emission of Nitrogen oxide (NOx) and Diesel Particulates (PM). The concern over Diesel particulate has increased in recent year because of health concerns. The objective of this research work is to identify the possibility of development of foam type diesel particulate filters (DPF) with indigenous ceramic materials which are easily available and cheaper. While developing the foam type diesel particulate filters, the main aim is to develop required porous structure for DPF with substantial strength, with low back pressure to minimize loss of engine performance, and with high trapping efficiency to reduce the particulate matter. The objective of this research work is also to investigate the effect of new developed filters without any regeneration arrangement and without any control or monitoring system, on the reduction of dry particulate matter and on the performance of diesel engine in terms of parameters like smoke density, back pressure, brake thermal efficiency and brake power. Use of DPF reduces smoke density with back pressure in acceptable limit. Parameters like brake power loss, increase in brake specific fuel consumption and decrease in brake thermal efficiency are caused by increased engine back pressure created by installation of the DPF system. This power penalty is within permissible limits, but can be further reduced by incorporating a regeneration system.

Ceramic Composite Diesel Filter Trap

2009 ◽  
Author(s):  
Nishikant V. Deshpande ◽  
Suhas C. Kongre ◽  
Piyush N. Deshpande ◽  
Mahul Indani ◽  
Rajan Singh
Keyword(s):  
Particulate Matter ◽  
Diesel Engine ◽  
Pore Size ◽  
Research Work ◽  
Pressure Rise ◽  
Engine Performance ◽  
Back Pressure ◽  
Ceramic Filter ◽  
Distinct Advantage ◽  
Particulate Emission

Diesel engine is a major source of power of the future but the major growing concern is the emissions of nitrogen oxides and diesel particulates. This work deals with the particulate emission control of diesel engine exhaust using ceramic filter. The selection of CFT with suitable size, geometry, cell density, wall thickness and microstructure becomes most important. In order to achieve required particulate matter emission limits and lower backpressure, optimization of porosity, pore size distribution, mean pore size and pore connectivity in CFT is crucial. CFT are developed and tested on the basis of porosity, diameter and length of CFT with necessary recommended trials. Further experiments were carried out to understand the effect of porosity, diameter and length of CFT on the back pressure, rate of back pressure rise, filtration efficiency and break power of diesel engine. The investigation of the research work provides adequate relevant information about the development of ceramic type ceramic filter trap (CFT) with naturally available material and effect of CFT on particulate matter concentration and on engine performance. Use of CFT reduced smoke drastically without increasing back pressure beyond tolerable back pressure limit. Performance of developed CFT was compared with established CFT and matches with it. Cost of developed CFT is the distinct advantage which will promote cottage industries in undeveloped nations, and provide rural employment.

scholarly journals Impact of SO42−, Ca2+, and Mg2+ ions in Caspian Sea ion-engineered water on the rate of wettability alteration in carbonates

2020 ◽  
Vol 10 (8) ◽  
pp. 3281-3293
Author(s):  
Meruyet Bazhanova ◽  
Peyman Pourafshary
Keyword(s):  
Contact Angle ◽  
Caspian Sea ◽  
Sea Water ◽  
Research Work ◽  
Spontaneous Imbibition ◽  
Ion Concentration ◽  
Reservoir Rock ◽  
Water Flooding ◽  
Wettability Alteration ◽  
Short Period

Abstract Tuning the salinity and concentration of potential-determining ions, such as Mg2+, Ca2+, and SO42−, could alter the wettability toward a more water-wet state. The rate of alteration in carbonate rock wettability is a critical parameter to design the duration of the ion-engineered water flooding. Characteristic experiments, such as dynamic contact angle and pH measurements, ion chromatography, and spontaneous imbibition, are applied to study the rate of wettability alteration using different samples of ion-engineered water. Our study shows that the Caspian Sea water (CSW) with a salinity of 15,000 ppm is an efficient displacing fluid as it can initiate the multi-ion exchange (MIE) mechanism and alter the wettability from 86° to 35° within 2 d. The adjustment of salinity and active ion concentration makes the MIE mechanism much faster. For example, with five times diluted CSW, the same change in wettability is only achieved only within 9 h. Spiking the concentration of Ca2+ and SO42− ions is used to further shift the contact angle to 22° within 9 h. Spontaneous imbibition tests demonstrate that the rate of oil production doubles as a result of the ion-engineered brine due to the faster MIE process. The results obtained from this research work suggest that even a short period of interaction with optimized engineered water can affect the brine, oil, and carbonates interactions and change the reservoir rock initial wettability from neutral to strongly water-wet state. This allows to efficiently design engineered water flooding based on CSW in the field scale and make such projects more profitable.

Comparisons on Flow and Temperature Fields for Water-Collecting Box of Diesel Exhaust System

2011 ◽  
Vol 199-200 ◽  
pp. 1532-1536 ◽  
Author(s):  
Xiao Chuan Wang ◽  
Guo He ◽  
Xing Long Pan ◽  
Xiao Ying Shi
Keyword(s):  
Sea Water ◽  
Reverse Flow ◽  
Temperature Drop ◽  
Three Dimensional ◽  
Exhaust System ◽  
Temperature Fields ◽  
Exhaust Gas ◽  
Three Dimensional Model ◽  
Computational Fluid Dynamics Cfd ◽  
Storage Cells

The storage cells of conventional submarines are usually charged up by in the snorkeling state, when the diesel engines that charge the storage cells work underwater. The reverse flow of sea water into the diesel engine from the exhaust pipelines can be avoided effectively by using a water-collecting box (WCB), which has other functions as well. In this paper, a three-dimensional model of WCB was established and based on which the flow and temperature fields were studied by computational fluid dynamics (CFD) computations. From the comparison of distribution on interior fields for four different structural WCBs, an optimized scheme of enhancing the cooling effect and not raising the exhausting resistance was probed. The results show that the temperature drop of exhaust gas after washing the WCB IV (WCB with truncated tubes) is 40 percent higher than that of the WCB I, and the pressure drop has a low of 3 percent as well. The comprehensive characteristics of WCB IV are foremost between the four WCBs.

Experimental Analysis of Diesel Engine Exhaust Gas Coupled With Water Desalination for Improved Potable Water Production

2015 ◽  
Author(s):  
Hitesh Panchal ◽  
Vipul Patel ◽  
Vinod Prajapati ◽  
Dharmendra Patel ◽  
Haresh Patel ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Potable Water ◽  
Waste Heat ◽  
Saline Water ◽  
Research Work ◽  
Water Desalination ◽  
Exhaust Gas ◽  
Water Production ◽  
Gas Temperature ◽  
Engine Exhaust

Exhaust gas temperature of diesel engine is higher compared with a petrol engine and also creates higher pollution in the environment. Exhaust gas recirculation system and many other systems have used for reuse of exhaust gas to improve the performance of diesel engine, but the use of diesel engine for production of potable water production is still unattended by the researchers. The main aim of this research work is to use the waste heat of exhaust gas for potable water production from the low capacity desalination system integrated with evaporator and condenser unit. In this work, single pass evaporator and water cooled condenser used for evaporation and condensation of saline water were designed and fabricated by locally available materials. The experiments were performed on a 10 HP Diesel engine with varying the load to get potable water. It has found that, 4.2 Liter/hr of potable water is obtained from the exhaust gas without varying the performance of the engine. Also, it has found that, temperature of saline water is heated more than 70 degrees Celsius in the condenser unit.

scholarly journals Influence of exhaust gas recirculation on performance and emissions of diesel engine Vikyno RV125-2

2015 ◽  
Vol 18 (4) ◽  
pp. 48-54
Author(s):  
Khai Le Duy Nguyen ◽  
Tri Minh Nguyen
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Three Dimensional ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Research Results ◽  
Direct Injection Diesel Engine ◽  
Performance And Emissions ◽  
Gas Recirculation ◽  
Engine Power

This paper presents a research on the influence of exhaust gas recirculation (EGR) on performance and emissions of direct injection diesel engine VIKYNO RV125-2 using three-dimensional CFD code KIVA-3V. In this study, the engine runs at 2400 rpm, 80% nominal load, and EGR concentration is changed from 0% to 40%. Research results indicate that with 20% EGR, the engine power is reduced 3,16%, while the concentrations of both NOx and soot are reduced 12,11% and 67,1%, respectively.

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