Piston Cooling Research Articles

Retracted: Research on the Flow Control of a Piston Cooling Nozzle

Retracted: Research on the Flow Control of a Piston Cooling Nozzle

Research on the Flow Control of a Piston Cooling Nozzle

The flow rate of a piston cooling nozzle is usually adjusted by changing the parameters of convergent length and inner diameter of the nozzle in engineering. However, the influence law and quantitative relationship between the flow rate and them are not clear. In this paper, the structural model and three-dimensional model of internal flow field of piston cooling nozzle are established by analyzing the structural characteristics and actual working conditions of piston cooling nozzles. Based on Fluent software, the flow field of piston cooling nozzles is simulated and analyzed. The distribution of velocity and pressure inside the piston cooling nozzle are obtained. The flow rate of fluid field is also obtained inside a piston cooling nozzle. In addition, the variation law of flow rate of the piston cooling nozzle is studied with the increasing of nozzle convergent length and diameter through several simulation experiments, respectively. The results show that the flow rate of piston cooling nozzle decreases linearly with the increase of the nozzle closing length. The flow rate of nozzle increases nonlinearly with the increase of the convergent diameter. Compared with the convergent length, the change of convergent diameter has a greater influence on the flow rate of piston cooling nozzles. Finally, the analytical expression of the flow rate of piston cooling nozzle about the convergent diameter is obtained, which is of great value and guiding significance to the nozzle engineering design.

CFD Simulation of Oil Jet Piston Cooling Applied to Pistons with Cooling Gallery

<div class="section abstract"><div class="htmlview paragraph">Efficient cooling of pistons with oil jets can avoid engine failures due to exceeded piston temperatures of thermally high-loaded combustion engines and can contribute to fuel consumption savings. To reduce expensive and time-consuming engine testing during product development, computational fluid dynamics (CFD) simulations help to quantify the piston cooling performance and provide detailed insights into the complex interactions between oil, air, and piston already in the design phase. The durability of new piston design approaches, such as integrated advanced cooling galleries or highly resistant materials like steel, can be evaluated including the use of alternative fuels, such as compressed natural gas (CNG), hydrogen, alcohols, or e-fuels. A new CFD simulation methodology for oil-jet piston cooling has been developed to investigate the cooling efficiency considering various piston cooling geometries and operational parameters. Method, software, and tools were already available from a former common research project of Ford and RWTH Aachen University where the level set and volume of fluid methods have been compared. Several applications of oil-jet piston cooling have been investigated on Ford engines. One example describes a gallery cooled CNG piston for a gas engine to resist the increased thermal load of the methane combustion. Another application considers a steel piston for a diesel engine with enlarged cross-sections within the cooling gallery to handle higher metal temperatures coming along with steel to avoid oil coking. For both examples, various engine speeds and oil-jet volume flow rates have been investigated. Results for each case are the transient oil flow including the oil filling process of the cooling gallery, the oil filling ratio, and the total heat transfer. Overall, the analyses show that modern CFD tools are a powerful way for investigating active cooling strategies for pistons to improve the efficiency of internal combustion engines and to reduce emissions.</div></div>

Oil Jets Piston Cooling: A Numerical Methodology for the Estimation of Heat Transfer Coefficients and Optimization of the Piston Temperature Field Through an Ai-Guided Genetic Algorithm

Oil Jets Piston Cooling: A Numerical Methodology for the Estimation of Heat Transfer Coefficients and Optimization of the Piston Temperature Field Through an Ai-Guided Genetic Algorithm

CFD Simulation of Oil Jets for Piston Cooling Applications Comparing the Level Set and the Volume of Fluid Method

<div class="section abstract"><div class="htmlview paragraph">A new CFD simulation model and methodology for oil jet piston cooling has been developed using the modern level set approach. In contrast to the widely used volume of fluid (VOF) method, the level set approach explicitly tracks the interface surface between oil and air, using an additional field equation. The method has been extensively tested on two- and three-dimensional examples using results from literature for comparison. Furthermore, several applications of oil jet piston cooling on Ford engines have been investigated and demonstrated. For example, three-dimensional simulations of piston cooling nozzle jets on a diesel engine have been calculated and compared to test-rig measurements. Laminar jets, as well as jets with droplets and fully atomized jets, have been simulated using realistic material properties, surface tension, and gravity. Simulations of cooling jets on the undercrown of a gasoline piston and on a moving piston with a cooling gallery have been investigated and compared to test-rig measurements. Results of a VOF model with the CFD software STAR-CCM+ used in the Ford CAE workflow have been compared to the new level set method. Despite using different computational approaches (level set versus volume of fluid method), the results are similar for laminar jets. Differences occur for semi-turbulent and atomized oil jets with many droplets, which need highly resolved meshes. All in all, the modern CFD tools are a powerful way for investigating active cooling strategies for pistons in order to improve the efficiency of internal combustion engines and to reduce emissions.</div></div>

Numerical Analysis of the Effect of Piston Cooling Gallery Design on Heat Transfer in an Internal Combustion Engine

Internal combustion engines are important machines that make human life easier. Internal combustion engines are developing day by day and higher power density engines are produced. Besides, strict standards of emission and fuel economy are forcing automotive manufacturers to produce environment-friendly engines. While manufacturers produce engines in accordance with these standards, they also do various studies in order not to reduce performance. One of the most important of these studies is the development of thermal management. Good cooling of internal combustion engine pistons, which are exposed to high pressures and temperatures during the combustion process, is an important consideration for the development of the thermal management. In this study; it is aimed to investigate the effect of design differences on piston cooling by using different designs for the cooling gallery located in the head region of an internal combustion engine piston. For this purpose, thermal analysis of an internal combustion engine piston was performed for different cooling gallery designs and the results of the analysis of each design were compared. In addition, the results of the analysis were compared with the heat transfer rates in the literature.

Piston Cooling Nozzle Oil Jet Evaluation Using CFD and a High Speed Camera

Piston Cooling Nozzle Oil Jet Evaluation Using CFD and a High Speed Camera

Design and Moldflow Analysis of Piston Cooling Nozzle in Automobiles

Automobile industries have shown great interest in replacing metal to plastic parts in order to reduce the cost and weight of the components. This can be achieved mostly be replacing metal component with injection molded components. Our study deals with the use of mold flow simulation in as a case study of metal to plastic conversion of the automobile component piston cooling nozzle. In this context the aluminium piston cooling nozzle is replaced by Nylon66+30GF piston cooling nozzle. Then based on the final product design, hand injection mold of the component was designed and manufactured. Finally the plastic part has to be tested for the working conditions, its performance in usage and compared with the aluminium part. Keywords: Metal to Plastic, Finite Element Analysis, Piston Cooling Nozzle

Design and Moldflow Analysis of Piston Cooling Nozzle in Automobiles

Automobile industries have shown great interest in replacing metal to plastic parts in order to reduce the cost and weight of the components. This can be achieved mostly be replacing metal component with injection molded components. Our study deals with the use of mold flow simulation in as a case study of metal to plastic conversion of the automobile component piston cooling nozzle. In this context the aluminium piston cooling nozzle is replaced by Nylon66+30GF piston cooling nozzle. Then based on the final product design, hand injection mold of the component was designed and manufactured. Finally the plastic part has to be tested for the working conditions, its performance in usage and compared with the aluminium part.

Numerical Simulation on the Flow and Heat Transfer Process of Nanofluids Inside a Piston Cooling Gallery

Copper and diamond nanoparticles with diameters of 50 nm are added into conventional engine oil, respectively, to preparetwo new types of nanofluids, which are further used as the heat transfer medium for the piston cooling gallery. Detailed oil flow and heat transfer processes of copper-oil and diamond-oil nanofluids, with the volume fractions of 1%, 2%, and 3% have been numerically investigated through a coupled VOF/Level-Set method. Research on oil fill ratio (OFR) and heat transfer coefficient (HTC) distributions at different crank angles has been conducted under the engine operation speed of 2000 r/min.

The Effect of Piston Cooling Jets on Diesel Engine Piston Temperatures, Emissions and Fuel Consumption

The Effect of Piston Cooling Jets on Diesel Engine Piston Temperatures, Emissions and Fuel Consumption

Visualization of Flow Pattern in Piston Cooling Channel

Visualization of Flow Pattern in Piston Cooling Channel

Enhanced Heat Transfer of Shaker-Bored Piston Cooling Channel with Twisted Tape Insert

This experimental study investigates the heat transfer augmentation in a reciprocating anti-gravity open thermosyphon using a twisted tape insert with relevance to the “shaker-bored” piston cooling system for marine propulsive diesel engine. A selection of experimental data illustrates the interactive effects of inertial, reciprocating, and buoyancy forces on heat transfer in the anti-gravity open thermosyphon with and without a twisted tape insert for subcooled and superheated conditions. The impacts of gravitational buoyancy on heat transfer in the static plain thermosyphon tube are reversed from impairing to improving heat transfer when the flow condition yields from subcooled to superheated condition. In the static thermosyphon tube fitted with twisted tape insert and in the reciprocating thermosyphon tubes with and without twisted tape insert, the buoyancy interactions enhance heat transfer coefficients. Due to the isolated reciprocating force effect, heat transfer coefficients are initially impaired from the static levels at low pulsating numbers but recovered to be enhanced at high pulsating numbers in the reciprocating plain thermosyphon tube. For the reciprocating thermosyphon tube fitted with a twisted tape insert, the isolated reciprocating force effect consistently improves heat transfer. The impacts of isolated reciprocating force and buoyancy interaction on heat transfer are Reynolds number-dependent. Heat transfer coefficients in the reciprocating thermosyphon tube fitted with the twisted tape insert could be augmented to the range of 1.2–6 times of plain tube levels. A set of empirical heat transfer correlations that considers the synergistic effects of inertial force, reciprocating force, and buoyancy interaction in the reciprocating anti-gravity open thermosyphon tube fitted with a twisted tape insert is developed to assist the design activity of the piston-cooling system.

Heat Transfer in Reciprocating Planar Curved Tube With Piston Cooling Application

This paper describes an experimental study of heat transfer in a reciprocating planar curved tube that simulates a cooling passage in piston. The coupled inertial, centrifugal, and reciprocating forces in the reciprocating curved tube interact with buoyancy to exhibit a synergistic effect on heat transfer. For the present experimental conditions, the local Nusselt numbers in the reciprocating curved tube are in the range of 0.6–1.15 times of static tube levels. Without buoyancy interaction, the coupled reciprocating and centrifugal force effect causes the heat transfer to be initially reduced from the static level but recovered when the reciprocating force is further increased. Heat transfer improvement and impediment could be superimposed by the location-dependent buoyancy effect. The empirical heat transfer correlation has been developed to permit the evaluation of the individual and interactive effects of inertial, centrifugal, and reciprocating forces with and without buoyancy interaction on local heat transfer in a reciprocating planar curved tube.

Heat Transfer in Reciprocating Spiral Tube with Piston Cooling Application

This paper describes a detailed experimental investigation of heat transfer in a reciprocating spiral tube with particular reference to the piston cooling application. The flow studied is turbulent upon entering the coils but transits into laminar in the further downstream of the coils. A selection of heat transfer measurements with which the physics of pulsating and buoyancy forces interactively affect the heat transfer along the inner and outer edges of the reciprocating coiled tube is illustrated. The pulsating force with buoyancy interaction causes the considerable heat transfer modifications from the static results. Although enhancing the buoyancy level improves heat transfer, the local Nusselt number in the reciprocating coils is initially impaired from the static value with weak reciprocation; but recovered at the higher level of pulsating force. This study focuses on the development of the experimental procedure that could lead to a physically consistent empirical correlation, which assists to evaluate the local heat transfer in the reciprocating coils by permitting the individual and interactive effects of centrifugal force, torsional force, pulsating force and reciprocating buoyancy on the forced convection to be quantified.

Forced Convective Heat Transfer of Parallel-Mode Reciprocating Tube Fitted With a Twisted Tape With Application to Piston Cooling

This experimental study, motivated by the need to improve the cooling performance of a piston in a marine propulsive diesel engine, investigated turbulent flow heat transfer in a reciprocating tube fitted with a twisted-tape insert. The nonreciprocating experimental data, obtained from the tube fitted with twisted tape, confirmed that heat-transfer augmentation from plain-tube level occurs. When the test tube reciprocated, buoyancy effects became appreciable, and interacted with the reciprocating and inertial forces to provide considerable heat transfer modifications from nonreciprocating situation. When the reciprocating forces were relatively weak, a range of heat-transfer impediments, that could reduce local Nusselt numbers to levels of about 53% of nonreciprocating values, was observed. A further increase of the relative strength of the reciprocating force resulted in a subsequent heat-transfer recovery, and eventually led to heat-transfer enhancements relative to the nonreciprocating situation. For design considerations, heat-transfer enhancement due to the twisted-tape insert was confirmed, but the impediments from nonreciprocating levels at lower values of pulsating numbers needs particular attention in order to avoid overheating situations.

Heat Transfer of Confined Impinging Jet onto Spherically Concave Surface with Piston Cooling Application.

This paper describes a detailed experimental investigation of heat transfer for confined impinging jet onto spherically concave surface with piston cooling application. The experimental conditions involved several nominal Reynolds numbers renging from 17 500 to 43 200 with five different reciprocating frequencies, namely 0, 0.833, 1.25, 1.67 and 2.08 Hz. It resulted in the pulsating number, which represented the ratio of reciprocating force to inertial force effect, varying from 0 to 1.85E-4. Along the spherically concave heating surface the evolution of flow structure from separation point into laminar and then turbulent annular flows was demonstrated by examining the variations of power index suffixed to Reynolds number in the non-reciprocating Nusselt number correlations. The typical effects of flow reciprocation on heat transfer were then illustrated by examining the distributions of temporal Nusselt number variation along the heating surface. When test section reciprocated, the Nusselt numbers at measurement locations periodically oscillated and the amplitude of such temporal Nusselt number variation was mostly pronounced at the stagnation point and became location and Reynolds number dependent. At the stagnation point, there were coupling effects of Reynolds and pulsating numbers on heat transfer and, in general, the heat transfer level increased with the increase of Reynolds or pulsating numbers while kept one of these two flow parameters unchanged. At Reynolds and pulsating numbers of 40 000 and 8.41E-5, the reciprocating Nusselt number value at the stagnation point could be increased up to a level about 3.2 times of the non-reciprocating level. Less reciprocating effects were found in the spherically concave heating area ; and reciprocation reduced the time-averaged heat transfer to the levels abut 80%-95% of non-reciprocating heat transfer values after flow passed the concave surface. As the reciprocating force significantly modified the heat transfer from non-reciprocating situation, it needed to account for the effect of reciprocating motion on the heat transfer within the coolant channels of piston in order to achieve the optimum design of cooling system.

Influence of Reciprocating Motion on Heat Transfer Inside a Ribbed Duct with Application to Piston Cooling in Marine Diesel Engines

This paper presents the results of an experimental study aimed at investigating the effect of reciprocating motion on the heat transfer for the flow inside a square ribbed enclosure. This flow configuration was a modification of the modern cooling system within a reciprocating piston of a marine heavy diesel engine. Initially, the heat transfer characteristics for the ribbed duct flow were examined and validated by comparing the present data with the relevant publications. Significant heat transfer enhancements detected from the nonreciprocating forced convection tests suggested the potential for heat transfer improvement using ribbed coolant channel. For the shaking effect on the cooling performance of the ribbed enclosure, a heat transfer impediment near which the thermal boundary layers were initiated was found when the reciprocating force was relatively low. Further increase of the reciprocating force or the level of heating power enhanced heat transfer. At the highest reciprocating speed tested, the heat transfer could be increased to a level about 145% of the equivalent stationary case. This study clarified that the circular ribs could be added inside the cooling passages in order to improve the cooling performance of the piston.

Thermal Analysis of a Piston Cooling System with Reciprocating Heat Pipes

The reciprocating heat pipe is a very promising technology in engine piston cooling, especially for heavy-duty diesel engines. The concept of the reciprocating heat pipe is verified through the experimental observation of a transparent heat pipe and by thermal testing of a copper/ water reciprocating heat pipe. A comparative thermal analysis on the reciprocating heat pipe and gallery cooling systems is performed. The approximate analytical results show that the piston ring groove temperature can be significantly reduced using heat pipe cooling technology, which could contribute to an increase in engine thermal efficiency and a reduction in environmental pollution.