Cylinder Compression Research Articles

Acoustic radiation force on a compressible cylinder in the standing surface acoustic wave (SSAW)

In this work, the radiation force exerted by the standing surface acoustic wave (SSAW) on a compressible cylinder in inviscid fluids is derived. The formula obtained in plane standing waves fails to calculate the radiation force on the cylinder in the SSAW. The Rayleigh angle is introduced to extend the prior formula. According to our expressions, the radiation force can not only repel the cylinder but also attract it in the direction perpendicular to the piezoelectric substrate. The Rayleigh angle can be used to actively tune the equilibrium positions (pressure nodes or antinodes) in the SSAW. Additionally, it can also be used to manipulate bubbles. Thus, our expressions have great potential in the SSAW-based applications.

Effect of diglyme addition on performance and emission characteristics of hybrid minor vegetable oil blends (rubber seed and babassu oil) in a tractor engine – an experimental study

ABSTRACTThe present study is intended to investigate the effect of hybrid minor vegetable oil blends in twin cylinder compression ignition (CI) engines used in tractors on performance, emission and combustion characteristics. Rubber seed oil (RSO) and babassu oil (BSO) are blended in various proportions of 75:25, 50:50 and 25:75 and tested at a constant speed and variable load conditions. Brake thermal efficiency (BTE) for diesel is 32.2% and reduces for RSO, BSO and its blends. Minimum BTE is observed for R75B25, which is 27.7%. HC, CO, and smoke emissions are higher with RSO, BSO and their blends compared to diesel at all load conditions. NO emission for vegetable oil blends is lower compared to diesel due to poor combustion. Combustion of RSO, BSO and their blends started late with lower premixed combustion and slower combustion increased the diffusion combustion. Hence, the R50B50 blend is identified as the best blend for CI engines accessible in villages. Diglyme (DGE), an oxygenate, is blended 20% with R50B50 blend. At 100% load, BTE for R50B50 + DGE 20 is improved by 6% compared to R50B50 and on a par with diesel. The blend also reduced HC, CO and smoke emissions with slightly higher NO emission due to performance improvement.

Investigation on rotating compression of porous cylinder under constant shear friction using FEM simulation

In this paper, a series of systematic studies on the rotating compression of porous cylinders by the FEM using DEFORM-3D analysis software are carried out. For a series of simulations, the forming conditions such as (1) the angular velocities from small to large are 0, 0.1, 0.25, 0.5, and 1 (rad/sec), respectively;(2) aspect ratio of porous cylinder (height-diameter ratio) are 0.75, 1, and 1.25, respectively;(3) the frictional factors are 0.3 and 0.7. Through different combinations of the above-mentioned variation factors, the characteristics of the rotating compression of porous cylinder can be explored. These rotating forming characteristics such as the compression force, the bulging ratio, the change in density, the rotating torque and so on can be investigated. The rotating compression characteristics of both porous and sound cylinders reveal lots of similarities and some differences. The main conclusions of this study are as follows: (1) as the rotating speed increases fast, the compression force of porous cylinder is whereas reduced. This phenomenon is different from the compression of sound cylinder; (2)the compression force under the lower aspect ratio can be reduced by the lubrication; (3)the relative density can be increased by increasing the rotating speed and reduction ratio; (4)the rotating torque is increased with higher rotating speed, higher frictional factor, and higher aspect ratio; (5)the bulging effect can be reduced by increasing the rotating speed, however it is increased by increasing the frictional factor.

Numerical analysis of the effects of compression ring wear and cylinder liner deformation on the thermal mixed lubrication performance of ring-liner system

The lubrication performance of roughness compression ring-cylinder liner system (CRCL) with axial-asymmetric new/worn compression ring and out-of-round cylinder liner is studied in this paper. By considering the oil film thermal effect, cavitation phenomenon, and surface roughness, the energy equations, mass conservation Jacoboson-Floberg-Olsson (JFO) cavitation algorithm, generalized average Reynolds equation, and Greenwood-Tripp asperity contact model are employed to investigate the frictional behaviors of CRCL. The oil film thickness, friction forces, wear, and power loss of CRCL are investigated at various wear stages of compression ring. The effects of the magnitude of cylinder liner deformation on the frictional characteristics of CRCL are also analyzed with consideration of compression ring conformability. Numerical results show that the deformation of cylinder liner and the wear of compression ring have a significant influence on the lubrication performance. It also suggests that the oil film thermal effect should be considered in the numerical analysis to provide an accurate prediction on the frictional behaviors of CRCL.

Manufacturing and testing of an α-type Stirling engine

This paper presents construction and performance tests of an α-type Stirling engine. Experiments were performed within the range of 1–4 bars charge pressure with air and helium as the working fluid. The outer surface of the expansion cylinder was heated with an electrical heater within the range of heater temperature 800–1000 °C with 50 °C increments. The outer surface of the compression cylinder was cooled by circulating water. Heater temperature and charge pressure were assumed as operating parameters and the engine torque was measured for different engine speeds with air and helium. The engine produced a maximum power of 30.7 W at 437 rpm engine speed, at the heater temperature of 1000 °C and 3.5 bars charge pressure with helium. Engine torque increased with the increase of charge pressure up to 3 bar then started to decrease. By looking the point of engine speed range of the engine, 1000 °C hot end temperature and 3 bar charge pressure was the optimal values.

Investigation effect of hydrogen addition on the performance and exhaust emissions of Pongamia pinnata biodiesel fueled compression ignition engine

ABSTRACTIn the recent decades, the energy demand for transport and industrial sector has increased considerably. Fossil fuels which were the major fuel source for decades are no more sustainable. Biodiesel is an efficient alternative compared to depleting fossil fuels. The prospect of biodiesel as the best alternative fuel is a reliable source compared to depleting fossil fuels. Hydrogen is also considered as an attractive alternative fuel producing low emission with improved engine performance. This paper investigates the performance and emission characteristics of a single cylinder compression ignition engine using hydrogen as an inducted fuel and biodiesel, aka Pongamia pinnata as injected fuel. The experiments are conducted for different quantities of hydrogen induction through the intake manifold in order to improve the performance of the engine. The performance parameters such as brake thermal efficiency, brake specific fuel consumption, exhaust temperature and emission quantities like HC, NOX, CO, CO2 of biodiesel fueled CI engine with variable mass flow rate of hydrogen are investigated. The performances of biodiesel combined with hydrogen at varying mass flow rates are also compared. The 10 LPM hydrogen induction with biodiesel provided 0.33% increase of brake thermal efficiency compared with diesel and increase of 3.24% to biodiesel at 80% loading conditions. The emission of HC decreased by 13 ppm, CO decreased by 0.02% by volume and CO2 decreased by 3.8% by volume for biodiesel with induction of hydrogen at 10 LPM to that of neat biodiesel for 80% load conditions.

ANALYTICAL APPROACH TO ROTATING COMPRESSION OF A POROUS CYLINDER CONSIDERING CONSTANT SHEAR FRICTION

The volume of the porous material in forming cannot be constant. However, the mass of the porous material remains constant; thereby making the derivations more complicated. A plastic mechanics analytical model with constant shear friction based on the slab method in this study is to explore the characteristics of the rotating compression of a porous cylinder. The effects of the frictional factor and frictional angle on the vertical stress, radial stress, average pressure, compression force, and rotating torque are systematically studied. The analytical results could be advantageous to the industries related to the forging of porous materials.

Maximum efficiencies for internal combustion engines: Thermodynamic limitations

The thermodynamic limitation for the maximum efficiencies of internal combustion engines is an important consideration for the design and development of future engines. Knowing these limits helps direct resources to those areas with the most potential for improvements. Using an engine cycle simulation which includes the first and second laws of thermodynamics, this study has determined the fundamental thermodynamics that are responsible for these limits. This work has considered an automotive engine and has quantified the maximum efficiencies starting with the most ideal conditions. These ideal conditions included no heat losses, no mechanical friction, lean operation, and short burn durations. Then, each of these idealizations is removed in a step-by-step fashion until a configuration that represents current engines is obtained. During this process, a systematic thermodynamic evaluation was completed to determine the fundamental reasons for the limitations of the maximum efficiencies. For the most ideal assumptions, for compression ratios of 20 and 30, the thermal efficiencies were 62.5% and 66.9%, respectively. These limits are largely a result of the combustion irreversibilities. As each of the idealizations is relaxed, the thermal efficiencies continue to decrease. High compression ratios are identified as an important aspect for high-efficiency engines. Cylinder heat transfer was found to be one of the largest impediments to high efficiency. Reducing cylinder heat transfer, however, is difficult and may not result in much direct increases of piston work due to decreases of the ratio of specific heats. Throughout this work, the importance of high values of the ratio of specific heats was identified as important for achieving high thermal efficiencies. Depending on the selection of constraints, different values may be given for the maximum thermal efficiency. These constraints include the allowed values for compression ratio, heat transfer, friction, stoichiometry, cylinder pressure, and pressure rise rate.

Experimental investigation of diesel/gasoline dual-fuel premixed compression ignition strategies for high thermal efficiency and high load extension

In this study, two different operating strategies of gasoline and diesel dual-fuel premixed compression ignition (PCI) were investigated by using a single cylinder compression ignition engine. Verification of high thermal efficiency potential under the low load condition and the suppression of the maximum in-cylinder pressure rise rate (PRRmax) under the relatively high load condition were considered in this study. Two approaches to implement dual-fuel PCI were considered. The first approach (A-mode PCI) was an early diesel injection with very leaner overall equivalence ratio condition. In this case, a high exhaust gas recirculation (EGR) rate was not needed because lean premixed combustion promised to provide low nitrogen oxides (NOx) and particulate matter (PM) emissions. The second method (B-mode PCI) involved the use of a high EGR rate to moderate dual-fuel combustion with adjusting diesel injection timing. The first operating strategy prolonged the ignition delay via early diesel injection and lean mixture condition; in this manner, a high EGR helped to increase ignition delay. The experimental result showed that the A-mode PCI strategy promised higher gross indicated thermal efficiency (GIE) than that of the B-mode PCI. However, the B-mode PCI strategy provided a lower PRRmax than that of the first case. By applying the A-mode PCI, which was implemented by the early diesel injection with overall lean premixed combustion, a high GIE of 47.8 % could be obtained under low speed and low load condition. In addition, the dual-fuel PCI operating range could be increased using a gross indicated mean effective pressure (gIMEP) of 14 bar at 2000 r/min with a low PRRmax of 7 bar/deg (constraint 10 bar/deg) by applying the B-mode PCI strategy, which split the heat release rate (HRR) peaks to enable smooth combustion.

Anisotropic elastic-plastic deformation of paper: Out-of-plane model

Laminated paperboard and paper is widely used in packaging products. Its out-of-plane properties play a crucial role in converting paperboard to a carton through the creasing and folding process. The aim of this study is to describe the out-of-plane mechanical response with an elastic-plastic model based on the observed experimental behavior. The model was derived from a thermodynamic framework and was based on the multiplicative split of the deformation gradient in the context of hyperelasticity. A structural tensor-based approach was applied to model the elastic deformation, while a multi-surface based yield criterion was adopted to describe the plastic behavior. The model considers both material densification and internal friction effects, which were observed experimentally. According to the experimental behavior, a quadratic yield locus under pure shear loading was assumed in the model. Finally, the model was validated with a cylinder compression test and found to capture the highly anisotropic, elastic-plastic behavior accurately.

Application of the boundary elements method for modeling of the fracture of cylindrical bodies by hydraulic fracturing

Experimental study of hydraulic fracturing of thick-walled cylinders with a central circular hole was carried out using the machine that creates a high oil pressure. Experiments on the compression fracture of the solid cylinders by diameter and rectangular parallelepipeds perpendicular to the ends were carried out with a multipurpose test machine Zwick / Roell Z100. Samples were made of GF-177 material based on cement. Ultimate stresses in the material under study were determined for three types of stress state: under compression, with a pure shear on the surface of the hole under frecking conditions and under a compound stress state under conditions of diametral compression of a solid cylinder. The value of the critical stress intensity factor of GF-177 material was obtained. The modeling of the fracturing process taking into account the inhomogeneity of the stress state near the hole was carried out using the boundary elements method (in the variant of the fictitious load method) and the gradient fracture criterion. Calculation results of the ultimate pressure were compared with values obtained analytically on the basis of the Lame solution and with experimental data.

Influences of dual bio-fuel (Jatropha biodiesel and turpentine oil) on single cylinder variable compression ratio diesel engine

The paper experimentally investigates the performance and exhaust emissions of a variable compression ratio engine fueled with 100%, 90%, 70% and 50% Jatropha bio-diesel and turpentine oil. In this paper, highly viscous Jatropha biodiesel is blended with relatively low viscosity turpentine oil in various proportions resulting in effective viscosity comparable with that of standard diesel with a view to developing a new alternative fuel which is comparable equally cost effective and eliminates dependency on conventional diesel fuel. Experimental analysis is carried out on ATE Make VCRE_MF single cylinder, naturally aspired, four stroke, and variable compression ratio diesel engine to study combustion performance and emission properties via conventional diesel fuel and different blends of Jatropha biodiesel with turpentine oil. Dual biofuel blend is found to be the greatest substitute to fossil (diesel) fuel in all aspects such as emissions and performance. Experiments have been accompanied at CR (compression ratio) of 15.5:1, 17:1, 18.5:1 and 20:1. Further, dual biofuel blend (JBT 50) resulted at full load and compression ratio 20, there was 2.17% increase in brake thermal efficiency and 13.04%, 17.5%, 4.21% and 30.8% decrease in CO, HC and NOx and smoke opacity respectively while CO2 was observed to increase by 11.04% respectively.

Performance, Combustion Characteristics and Emission Tests of Single Cylinder Engine Running on Fusel Oil - Diesel Blended (F20) Fuel

Alcohols produced from a renewable source are amongst the important alternative fuels for internal combustion engines. Investigations on alternative fuels for compression ignition engines regarded as one of the major research areas. This paper details an experimental examination of the performance and emissions in single cylinder compression ignition engines operating with fusel oil F20 and pure diesel F0 at five engine speeds and 50% engine load. The test results indicated that the engine power and torque slightly decrease with the F20 at low speeds compared with pure diesel. Further, the in-cylinder pressure was decreased at all engine speed for F20 in comparison with pure diesel. The volumetric efficiency and fuel consumption were increased for F20 due the low heating value of fusel oil. The results showed that CO2 and CO emissions were increased because of the water content, low heating value and low cetane number for fusel oil. The maximum reduction in NOx emissions was 18% for F20 at 1500 rpm.

The Recuperated Split Cycle - Experimental Combustion Data from a Single Cylinder Test Rig

The conventional Diesel cycles engine is now approaching the practical limits of efficiency. The recuperated split cycle engine is an alternative cycle with the potential to achieve higher efficiencies than could be achieved using a conventional engine cycle. In a split cycle engine, the compression and combustion strokes are performed in separate chambers. This enables direct cooling of the compression cylinder reducing compression work, intra cycle heat recovery and low heat rejection expansion. Previously reported analysis has shown that brake efficiencies approaching 60% are attainable, representing a 33% improvement over current advanced heavy duty diesel engine. However, the achievement of complete, stable, compression ignited combustion has remained elusive to date. The challenge is to induct hot high pressure charge air close to top dead centre into the combustion cylinder and then inject and burn the fuel before the piston has travelled significantly down the expansion stroke. In this paper, we report results from a single cylinder split cycle combustion research engine. Stable, rapid combustion was achieved at 800 rpm and 1200 rpm at the retarded timings required for a split cycle engine. The calculated rate of heat release was more rapid than typically observed on conventional compression ignition engine suggesting good mixing of the fuel and air during induction. One dimensional cycle analysis was used to calculate the implications of the test results on the full engine cycle which indicated class leading brake efficiencies approaching and possibly exceeding, 60% are possible from a split cycle engine.

Multi-failure theory of composite orthogrid sandwich cylinder

Under uniaxial compression, carbon fiber reinforced composite (CFRC) orthogrid sandwich cylinder has four potential failure modes, including global buckling, monocell buckling, rib buckling and material failure. The smearing method was applied to predict the equivalent stiffness and calculate the stresses of the skins and the orthogrid, providing fundaments to build the failure criteria. Theoretical models were established to reveal the failure modes and predict the ultimate load of the compressed orthogrid cylinder by the way of failure maps, providing a feasible way to optimally design CFRC anisogrid cylinder.

Real-time fast ultrasonic monitoring of concrete cracking using embedded piezoelectric transducers

This paper deals with the use of embedded piezoelectric transducers for ultrasonic monitoring of cracking in concrete. Based on the previous developments of our research team on that topic, we design a new data acquisition system which is able to interrogate the emitter-receiver pair up to 150 times per second. The system is based on low-voltage actuation (up to 20 V) and the signal-to-noise ratio is excellent due to the use of a voltage amplifier at the receiver side and the possibility to perform averages. With such a high measurement rate, we are able to follow brittle failure events such as the failure of a concrete cylinder in compression, which is the application example presented. In this application, we show that, in addition to the ultrasonic active monitoring of cracking, the system is also able to record the passive acoustic emission events which can be used as a complementary indicator of damage in the cylinder. We also demonstrate that because of the high level of stresses in compression, the damage indicator defined in our previous studies is not suited for crack monitoring due to the elastoacoustic effect. The amplitude of the first wave arrival is shown to be a robust alternative damage indicator allowing to follow accurately the three successive phases of cracking leading to the failure of the cylinder.

Behaviour of polygonal-shaped steel-tube columns filled with high-strength concrete

This paper presents an investigation on axially loaded polygonal-shaped steel-tube columns filled with high-strength concrete. The tubes had triangular, hexagonal and octagonal cross-sections, the concrete had a nominal concrete compressive cylinder strength of 100 MPa and the steel had a nominal yield strength of 285 MPa. For each tube cross-section, two identical specimens of concrete-filled tubes and one specimen of a hollow tube were examined. Load shortening, strain histories and failure modes were recorded and compared. Finite-element analysis with three different existing constitutive models of concrete were also developed and validated against the experimental results. The load-carrying capacities of the concrete-filled tubes were compared with the derived values from BS EN 1994-1-1:2004, ACI 318-11/AISC 360-16 and GB 50936-2014. The feasibility of current design standards for concrete-filled steel-tube columns of different cross-sections is discussed.

Numerical study on the lubrication performance of compression ring-cylinder liner system with spherical dimples.

The effects of surface texture on the lubrication performance of a compression ring-cylinder liner system are studied in this paper. By considering the surface roughness of the compression ring and cylinder liner, a mixed lubrication model is presented to investigate the tribological behaviors of a barrel-shaped compression ring-cylinder liner system with spherical dimples on the liner. In order to determine the rupture and reformulation positions of fluid film accurately, the Jacoboson-Floberg-Olsson (JFO) cavitation boundary condition is applied to the mixed lubrication model for ensuring the mass-conservative law. On this basis, the minimum oil film thickness and average friction forces in the compression ring-cylinder liner system are investigated under the engine-like conditions by changing the dimple area density, radius, and depth. The wear load, average friction forces, and power loss of the compression ring-cylinder liner system with and without dimples are also compared for different compression ring face profiles. The results show that the spherical dimples can produce a larger reduction of friction in mixed lubrication region, and reduce power loss significantly in the middle of the strokes. In addition, higher reduction percentages of average friction forces and wear are obtained for smaller crown height or larger axial width.

Behaviour of steel tubular members infilled with ultra high strength concrete

This study is motivated by increasingly prevalent use of high strength steel and concrete materials in high-rise buildings to achieve better structural performance with less material usage. Previous studies and many modern design codes place some limits on the strength of steel and concrete for designing steel-concrete composite members, attributed to insufficient test data and design experience on their applications in construction. With this research gap being identified, an experimental program has been carried out to investigate the composite behaviour of concrete filled steel tubes (CFST) employing high tensile strength steel (HTS) and ultra-high strength concrete (UHSC). Both concentric and eccentric compression loads were applied to evaluate the overall buckling resistances and moment-axial force interaction with second-order effect considered. The yield strength of HTS under the investigation was about 800N/mm2 and the concrete compressive cylinder strength was up to 200N/mm2. To examine the test results, the rotational stiffness of semi-rigid end supports was analytically derived and the stress-strain models of HTS and UHSC were properly calibrated to predict the composite behaviour through finite element analysis. The Eurocode 4 approach was then checked regarding its applicability to the said high- and ultra-high strength construction materials for composite design. A new database including 1160 test data was established to further study the reliability of the use of HTS and UHSC, and suggestions were made to extend the Eurocode 4 design approach.

Study on Flexural Behaviour of Ternary Blended Reinforced Self Compacting Concrete Beam with Conventional RCC Beam

The conventional concrete when used for structures having dense congested reinforcement, the problems such as external compaction and vibration needs special attention. In such case, the self compacting concrete (SCC) which has the properties like flow ability, passing and filling ability would be an obvious answer. All those SCC flow behavior was governed by EFNARC specifications. In present study, the combination type of SCC was prepared by replacing cement with silica fume (SF) and metakaolin (MK) along with optimum dosages of chemical admixtures. From the fresh property test, cube compressive strength and cylinder split tensile strength, optimum ternary mix was obtained. In order to study the flexural behavior, the optimum ternary mix was taken in which beam specimens of size 1200 mm x 100 mm x 200 mm was designed as singly reinforced section according to IS: 456-2000, Limit state method. Finally the comparative experimental analysis was made between conventional RCC and SCC beams of same grade in terms of flexural strength namely yield load & ultimate load, load- deflection curve, crack size and pattern respectively.