Further Investigations into the Benefits and Challenges of Eliminating Port Overlap in Wankel Rotary Engines

Abstract A research project is currently underway to develop small-scale internal combustion engines fueled by liquid hydrocarbons. The ultimate goal of the MEMS Rotary Internal Combustion Engine Project is to develop a liquid hydrocarbon fueled MEMS-size rotary internal combustion micro-engine capable of delivering power on the order of milli-watts. This research is part of a larger effort to develop a portable, autonomous power generation system with an order of magnitude improvement in energy density over alkaline or lithium-ion batteries. The rotary (Wankel-type) engine is well suited for the fabrication techniques developed in the integrated chip (IC) community and refined by the MicroElectroMechanical Systems (MEMS) field. Features of the rotary engine that lend itself to MEMS fabrication are its planar construction, high specific power, and self-valving operation. The project aims at developing a “micro-rotary” engine with an epitrochoidal-shaped housing under 1 mm3 in size and with a rotor swept volume of 0.08 mm3. To investigate engine behavior and design issues, larger-scale “mini-rotary” engines have been fabricated from steel. Mini-rotary engine chambers are approximately 1000 mm3 to 1700 mm3 in size and their displacements range from 78 mm3 to 348 mm3. A test bench for the mini-rotary engine has been developed and experiments have been conducted with gaseous-fueled mini-rotary engines to examine the effects of sealing, ignition, design, and thermal management on efficiency. Preliminary testing has shown net power output of up to 2.7 W at 9300 RPM. Testing has been performed using hydrogen-air mixtures and a range of spark and glow plug designs as the ignition source. Iterative design and testing of the mini-engine has lead to improved sealing designs. These particular designs are such that they can be incorporated into the fabrication of the micro-engine. Design and fabrication of a first generation meso-scale rotary engine has been completed using a SiC molding process developed at Case Western Reserve University. The fabrication of the micro-rotary engine is being conducted in U.C. Berkeley’s Microfabrication Laboratory. Testing of the mini-engine has lead to the conclusion that there are no fundamental phenomena that would prevent the operation of the micro-engine. However, heat loss and sealing issues are key for efficient operation of the micro-engine, and they must be taken into account in the design and fabrication of the micro-rotary engine. The mini-rotary engine design, testing, results and applications will be discussed in this paper.

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The Ensuring of Survivability of Wave Energy Stations Constructive Elements in Extreme Weather Conditions

E3S Web of Conferences ◽

10.1051/e3sconf/20199705049 ◽

2019 ◽

Vol 97 ◽

pp. 05049

Author(s):

Alexander Solovyev ◽

Dmitriy Solovyev ◽

Liubov Shilova

Keyword(s):

Wave Energy ◽

Weather Conditions ◽

Extreme Weather ◽

Wave Power ◽

Sea Waves ◽

Power Station ◽

Rotary Engines ◽

Water Layers

Current problems and the tasks of increasing the reliability of the equipment designs for utilizing the energy of sea waves are described in the article. The requirements for the protection of float and buoy structures from storm impacts by immersing them in undisturbed water layers using rotary engines articulated with a wave power station are formulated. Ways to protect wave converters from storm impacts are proposed.

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Numerical Study on Flow Field in a Peripheral Ported Rotary Engine Under the Action of Apex Seal Leakage

Journal of Fluids Engineering ◽

10.1115/1.4049117 ◽

2020 ◽

Author(s):

Baowei Fan ◽

Yuanguang Wang ◽

Jianfeng Pan ◽

Yaoyuan Zhang ◽

Yonghao Zeng

Keyword(s):

Velocity Field ◽

Flow Field ◽

Combustion Chamber ◽

Numerical Study ◽

Particle Image Velocimetry Data ◽

Calculation Model ◽

Flow Area ◽

Rotary Engine ◽

Unidirectional Flow ◽

Rotary Engines

Abstract Apex seal leakage is one of the main defects restricting the performance improvement of rotary engines. The aim of this study is to study the airflow movement in a peripheral ported rotary engine under the action of apex seal leakage. For this purpose, a 3D dynamic calculation model considering apex seal leakage was firstly established and verified by particle image velocimetry data. Furthermore, based on the established 3D model, the flow field in the combustion chamber under the four apex seal leakage gaps (0.02, 0.04, 0.06 and 0.08 mms) and the three engine revolution speeds (2000, 3500, and 5000 RPMs) was calculated. By comparing with the flow field under the condition without leakage, the influences of the existence of apex seal leakage on the velocity field, the turbulent kinetic energy and the volumetric efficiency in the combustion chamber were investigated. Thereinto, the influences of the existence of apex seal leakage on the velocity field is that at the intake stroke, a vortex formed in the middle of the combustion chamber under the condition without apex seal leakage, was intensified by the apex seal leakage action. At the compression stroke, irrespective of the condition with or without apex seal leakage, all vortexes in the combustion chamber are gradually broken into a unidirectional flow. However, there is an obvious "leakage flow area" at the end of combustion chamber due to the existence of apex seal leakage.

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