Influence of a High-Swirling Helical Port with Axisymmetric Piston Bowls on In-Cylinder Flow in a Small Diesel Engine
05 Apr 2016-
About: The article was published on 2016-04-05. It has received 1 citations till now. The article focuses on the topics: Piston & Diesel engine.
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TL;DR: In this paper, a spiral-helical shape with three different helical diameters (1D, 2D, 3D) and three port outlet angles (0, 1, 30, and 60 degrees) was developed to enhance the turbulence intensity and improve the mixing quality inside diesel engine cylinders.
Abstract: New induction manifold designs have been developed in this work to enhance the turbulence intensity and improve the mixing quality inside diesel engine cylinders. These new designs employ a spiral-helical shape with three different helical diameters (1D, 2D, 3D; where D is the inner diameter of the manifold) and three port outlet angles: 0 deg, 30 deg, and 60 deg. The new manifolds have been manufactured using three-dimensional printing technique. Computational fluid dynamics simulations have been conducted to estimate the turbulent kinetic energy (TKE) and the induction swirl generated by these new designs. The combustion characteristics that include the maximum pressure raise rate (dP/dθ) and the peak pressure inside the cylinder have been measured for a direct injection (DI) diesel engine utilizing these new manifold designs. In addition, engine performance and emissions have also been evaluated and compared with those of the normal manifold of the engine. It was found that the new manifolds with 1D helical diameter produce a high TKE and a reasonably strong induction swirl, while the ones with 2D and 3D generate lower TKEs and higher induction swirls than those of 1D. Therefore, dP/dθ and peak pressure were the highest with manifolds 1D, in particular manifold m (D, 30). Moreover, this manifold has provided the lowest fuel consumption with the engine load by about 28% reduction in comparison with the normal manifold. For engine emissions, m (D, 30) manifold has generated the lowest CO, SO2, and smoke emissions compared with the normal and other new manifolds as well, while the NO emission was the highest with this manifold.
8 citations
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01 Apr 2014
TL;DR: In this paper, a commercial CFD tool is used to carry out simulations of four different piston bowl geometries, at three engine loads with two different swirl ratios at each load point.
Abstract: Heat transfer losses are one of the largest loss contributions in a modern internal combustion engine. The aim of this study is to evaluate the contribution of the piston bowl type and swirl ratio to heat losses and performance. A commercial CFD tool is used to carry out simulations of four different piston bowl geometries, at three engine loads with two different swirl ratios at each load point. One of the geometries is used as a reference point, where CFD results are validated with engine test data. All other bowl geometries are scaled to the same compression ratio and make use of the same fuel injection, with a variation in the spray target between cases. The results show that the baseline case, which is of a conventional diesel bowl shape, provides the best emission performance, while a more open, tapered, lip-less combustion bowl is the most thermodynamically efficient. The results also show that the effects of swirl are not consequent throughout all piston geometries, as the flow field response to swirl variations is different in the various piston geometries. (Less)
21 citations
01 Jan 2010
TL;DR: In this paper, the authors used the computational fluid dynamics (CFD) code FLUENT to model complex combustion phenomenon in compression ignition (CI) engine with a single cylinder and a direct injection (DI) diesel engine.
Abstract: This paper describes the development and use of sub models for combustion analysis in direct injection (DI) diesel engine. In the present study the Computational Fluid dynamics (CFD) code FLUENT is used to model complex combustion phenomenon in compression ignition (CI) engine. The experiments were accomplished on single cylinder and DI engine, with full load condition at constant speed of 1500 rpm. Combustion parameters such as cylinder pressure, rate of pressure rise and heat release rate were obtained from experiment. The numerical modeling is solved by unsteady first order implicit, taking into account the effect of turbulence. For modeling turbulence Renormalization Group Theory (RNG) k e model is used. The submodels such as droplet collision model and Taylor Analogy Breakup (TAB) model are used for spray modeling. The wallfilm model is used to assess spraywall interaction. Modeling incylinder combustion, species transport and finiterate chemistry model is used with simplified chemistry reactions. The results obtained from modeling were compared with experimental investigation. Consequences in terms of pressure, rate of pressure rise and rate of heat release are presented. The rate of pressure rise and heat release rate were calculated from pressure based statistics. The modeling outcome is discussed in detail with combustion parameters. The results presented in this paper demonstrate that, the CFD modeling can be the reliable tool for modeling combustion of internal combustion engine.
19 citations
TL;DR: In this paper, a steady state air flow test rig was used to evaluate the global fluid-dynamic efficiency of the intake system, made by a swirled and a directed port, in terms of mass flow rate, flow coefficients and swirl number.
Abstract: The paper illustrates an experimental and numerical investigation of the flow generated by an intake port model for a heavy duty direct injection (HDDI) Diesel engine. Tests were carried out on a steady state air flow test rig to evaluate the global fluid-dynamic efficiency of the intake system, made by a swirled and a directed port, in terms of mass flow rate, flow coefficients and swirl number. In addition, because the global coefficients are not able to give flow details, the Laser Doppler Anemometry (LDA) technique was applied to obtain the local distribution of the air velocity within a test cylinder. The steady state air flow rig, made by a blower and the intake port model mounted on a plexiglas cylinder with optical accesses, was assembled to supply the, actual intake flow rate of the engine, setting the pressure drop across the intake ports at ΔP=300 and 500 mm of H 2 O. The flow coefficients and the swirl number were computed measuring the flow rate by a turbine flow meter and a paddle wheel to evaluate the air vortex speed into the cylinder test. The LDA technique was used to obtain the tangential and axial components of the flow velocity on two planes and along three diameters within the test cylinder. The computation was carried out by the fluid-dynamic code STAR-CD that solves the ensemble averaged conservation equations for mass, momentum and energy in steady state conditions with the turbulence model k-e. The grid, reproducing the geometry of the intake port and the real fluid system, was made using CAD data and the boundary conditions were the same as the experimental ones. Results of the computed mass flow rate, flow coefficients, and velocity profiles were compared to the experimental ones. The substantial agreement between experiments and computations suggests that an acceptable level of confidence may be assigned to calculations to design the intake port geometry of heavy duty Diesel engines.
16 citations
TL;DR: Wang et al. as mentioned in this paper combined the steady flow test and CFD numerical simulation to do structure study of diesel helical intake port, and the results basically analyzed that the flow characteristic of intake port was affected by above three parameters.
15 citations
01 Feb 1995
6 citations