Experimental and Dynamic Analysis of a Small-Scale Double-Acting Four-Cylinder α-Type Stirling Engine

This research studies the double-acting four-cylinder α-type Stirling engine. A numerical model is developed by combining the thermodynamic model and dynamic model to study the engine performance. The pressure values of the working zone calculated using the thermodynamic model are taken into the dynamic model to calculate the forces acting on the mechanism. Then, the dynamic model further calculates the displacement, velocity, and acceleration of the mechanism link to provide the pistons’ displacements for the thermodynamic model. The model is also validated using experimental data obtained from testing an engine prototype. Under a heating temperature of 1000 K, cooling temperature of 315 K, charged pressure of 10 bar, and loading torque of 0.33 Nm, the engine is capable of achieving a shaft power of 26.0 W at 754 rpm. In addition, the thermal properties and the transient behavior of the engine can be further simulated using the validated numerical model.

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A Study of Mesh Sheets of 3-kW Stirling Engine

E3S Web of Conferences ◽

10.1051/e3sconf/202131305001 ◽

2021 ◽

Vol 313 ◽

pp. 05001

Author(s):

Takeshi Enomoto ◽

Atsushi Matsuguchi ◽

Noboru Kagawa

Keyword(s):

Low Temperatures ◽

High Performance ◽

High Efficiency ◽

Heating Temperature ◽

Engine Performance ◽

Stirling Engine ◽

Working Fluid ◽

Heat Engines ◽

Exhaust Heat ◽

Regenerator Material

In recent years, the interest in low-pollution and high-efficiency heat engines has been increasing due to the growing awareness of environmental protection, and power generation at relatively low temperatures, such as use of exhaust heat and sunlight, has been attracting attention. Compared with other heat engines, Stirling engine is very important because it can be driven by any heat source at low temperatures, such as exhaust heat, and it does not emit exhaust gas. In order to realize a more efficient Stirling engine, it is essential to design a heat exchange system that is suitable for each component. Performance measurement and analysis on a new mesh regenerator material at low temperature difference using a 2-piston alpha-type 3-kW Stirling engine, NS03T are carried out. Mesh sheets developed for high performance Stirling engines can be designed with CAD and CAM technologies by etching process. For this study, M5 and M7 mesh sheets which are thin sheets of stainless steel with square holes in a grid arrangement, are used. With nitrogen and helium as the working fluid, the engine performance is measured by changing the charge pressure, heating temperature, and engine speed to clarify the flow resistance and heat transfer characteristics of the M5 and M7.

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Numerical Optimization of the β-Type Stirling Engine Performance Using the Variable-Step Simplified Conjugate Gradient Method

Energies ◽

10.3390/en14237835 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7835

Author(s):

Chin-Hsiang Cheng ◽

Duc-Thuan Phung

Keyword(s):

Conjugate Gradient Method ◽

Conjugate Gradient ◽

Gradient Method ◽

Thermodynamic Model ◽

Thermal Efficiency ◽

Engine Performance ◽

Stirling Engine ◽

Positive Effects ◽

Baseline Case ◽

Variable Step

This study focuses on optimizing a 100-W-class β-Type Stirling engine by combining the modified thermodynamic model and the variable-step simplified conjugate gradient (VSCGM) method. For the modified thermodynamic model, non-uniform pressure is directly introduced into the energy equation, so the indicated power and heat transfer rates can reach energy balance while the VSCGM is an updated version of the simplified conjugate gradient method (SCGM) with adaptive increments and step lengths to the optimization process; thus, it requires fewer iterations to reach the optimal solution than the SCGM. For the baseline case, the indicated power progressively raises from 88.2 to 210.2 W and the thermal efficiency increases from 34.8 to 46.4% before and after optimization, respectively. The study shows the VSCGM possesses robust property. All optimal results from the VSCGM are well-matched with those of the computational fluid dynamics (CFD) model. Heating temperature and rotation speed have positive effects on optimal engine performance. The optimal indicated power rises linearly with the charged pressure, whereas the optimal thermal efficiency tends to decrease. The study also points out that results of the modified thermodynamic model with fixed values of unknowns agree well with the CFD results at points far from the baseline case.

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Numerical model for predicting the performance and transient behavior of a gamma-type free piston Stirling engine

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2020.116375 ◽

2020 ◽

pp. 116375

Author(s):

Hang-Suin Yang

Keyword(s):

Numerical Model ◽

Transient Behavior ◽

Stirling Engine ◽

Free Piston ◽

Free Piston Stirling Engine

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Development of a Beta-Type Moderate-Temperature-Differential Stirling Engine Based on Computational and Experimental Methods

Energies ◽

10.3390/en13226029 ◽

2020 ◽

Vol 13 (22) ◽

pp. 6029

Author(s):

Chin-Hsiang Cheng ◽

Jhen-Syuan Huang

Keyword(s):

Dynamic Analysis ◽

Waste Heat ◽

Heating Temperature ◽

Stirling Engine ◽

Model Combining ◽

Cogeneration System ◽

Shaft Power ◽

Swept Volume ◽

The Impact ◽

Geometrical Dimensions

Stirling engine is a favorable technique in the application of waste heat recovery or cogeneration system. This paper aims at developing a beta-type Stirling engine which is operated at moderate heating temperature (773–973 K). Rhombic drive mechanism is utilized to make coaxial motion of displacer and piston. Based on the proposed dimensions, a theoretical model combining thermodynamic and dynamic analysis is built to predict the performance of the Stirling engine. Thermodynamic analysis deals with variations of properties in each chamber while dynamic analysis handles the resultant shaft torque produced by the Stirling engine. Furthermore, a prototype engine is manufactured, and experimental test is carried out to validate the simulated results in this research. Under heating temperature of 973 K, charged pressure of 8 bar, rotation speed of 1944 rpm, shaft power of 68 W is obtained from the prototype Stirling engine. Power density is calculated to be 1.889 W-c.c.−1 by theoretical prediction and 1.725 W-c.c.−1 by tested result. The impact of the geometrical dimensions is investigated to survey the optimal piston diameter which is related to compression ratio and swept volume.

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An Investigation of a Self-Pressurized Alpha V-Type Stirling Engine Converted Diesel Engine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.699.695 ◽

2014 ◽

Vol 699 ◽

pp. 695-701 ◽

Cited By ~ 1

Author(s):

Mohamad Yusof ◽

Z.A. Zainal ◽

N.A. Farid ◽

M.A. Miskam

Keyword(s):

Diesel Engine ◽

Mass Production ◽

Electrical Power ◽

Engine Performance ◽

Stirling Engine ◽

Liquefied Petroleum Gas ◽

Brake Thermal Efficiency ◽

Brake Power ◽

Shaft Power ◽

Load Conditions

This study reports the investigation results of 194cc. alpha V-type Stirling engine converted from a four-stroke diesel engine that operated in self-pressurized mode. Tests were conducted with air as the working gas and liquefied petroleum gas (LPG) as the heat source. The engine started operating at 600 °C for hot cylinder temperature and 60 °C for cold cylinder temperature, respectively. At heat input of 1100 J/s, the engine performance was successfully tested at both no load and load conditions. For mechanical shaft power assessment, the engine approximately produced a maximum brake power of 7 W, brake thermal efficiency of 0.6% at 717 rpm speed, 811 °C hot cylinder temperature and 96 °C cold cylinder temperature. For electrical power assessment, the engine was capable of generating a maximum electrical output power of 1.7 We at 657 rpm speed, 855 °C hot cylinder temperature and 98 °C cold cylinder temperature. Despite its low engine performance, the study of alpha V-type Stirling engine is a worthwhile step towards clean and sustainable energy in mass production.

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Performance Analysis of the Small-Scale α-Type Stirling Engine Using Computational Fluid Dynamics Tools

Journal of Energy Resources Technology ◽

10.1115/1.4037810 ◽

2017 ◽

Vol 140 (3) ◽

Cited By ~ 10

Author(s):

Zbigniew Buliński ◽

Ireneusz Szczygieł ◽

Adam Kabaj ◽

Tomasz Krysiński ◽

Paweł Gładysz ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Numerical Model ◽

Stirling Engine ◽

Coefficient Of Performance ◽

Navier Stokes ◽

Small Scale ◽

Ansys Fluent ◽

Fluent Software ◽

Energy Equations

This paper presents the computational fluid dynamics (CFD) model of small-scale α-type Stirling engine. The developed mathematical model comprises of unsteady Reynolds averaged Navier–Stokes set of equations, i.e., continuity, momentum, and energy equations; turbulence was modeled using standard κ–ω model. Moreover, presented numerical model covers all modes of heat transfer inside the engine: conduction, convection, and radiation. The model was built in the framework of the commercial CFD software ANSYS fluent. Piston movements were modeled using dynamic mesh capability in ANSYS fluent; their movement kinematics was described based on the crankshaft geometry and it was implemented in the model using user-defined functions written in C programming language and compiled with a core of the ANSYS fluent software. The developed numerical model was used to assess the performance of the analyzed Stirling engine. For this purpose, different performance measures were defined, including coefficient of performance (COP), exergy efficiency, and irreversibility factor. The proposed measures were applied to evaluate the influence of different heating strategies of the small-scale α-type Stirling engine.

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Performance analysis of free piston Stirling engine based on the phasor notation method

E3S Web of Conferences ◽

10.1051/e3sconf/202131302004 ◽

2021 ◽

Vol 313 ◽

pp. 02004

Author(s):

Pengfan Chen ◽

Ying Wang ◽

Wenhao Ding ◽

Yafeng Niu ◽

Zibo Lin ◽

...

Keyword(s):

Performance Analysis ◽

Numerical Model ◽

Heating Temperature ◽

Coupled Model ◽

Couple System ◽

Stirling Engine ◽

Dynamic Parameters ◽

Free Piston ◽

Free Piston Stirling Engine ◽

Analysis Prediction

The free piston Stirling engine (FPSE) is a couple system of dynamics and thermodynamics. Due to the complicated and interactive relationships between the dynamic parameters and thermodynamic parameters, the performance of the FPSE is always difficult to predict and evaluate. The phasor notation method is proposed based on a thermodynamic-dynamic coupled model of a beta-type FPSE in this paper. The output power and efficiency under the different heating temperature and charging pressure are analysed and compared. In addition, based on the Sage numerical model, the influences of heating temperature and charging pressure on the pistons’ displacement amplitudes, power work and efficiency are revealed. This study can provide the assistance for the performance analysis, prediction and optimization of the FPSE.

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