scholarly journals Stirling-Engine in a Novel Alphagamma Configuration – a Key for Maintenance-free Operation

2021 ◽  
Vol 313 ◽  
pp. 08006
Author(s):  
Josef Frauscher ◽  
Franz Diermaier ◽  
Hans-Jürgen Brandt ◽  
Michael Gschwendtner
Keyword(s):  
Experimental Data ◽  
Friction And Wear ◽  
Stirling Engine ◽  
Work Output ◽  
Polytropic Model ◽  
Stirling Engines ◽  
Conducting Research ◽  
Development Step ◽  
Good Agreement ◽  
The Ideal

Since 2001, Frauscher Thermal Motors have been conducting research in the field of thermodynamic machines, in particular Stirling engines of various types. One important development step is the invention of a Stirling engine in an alphagamma® configuration. In this configuration, the expansion piston is designed as a differential piston with its ring surface connected to the cold volume. In this paper, the design advantages of the alphagamma® configuration in comparison with a traditional alpha configuration are shown analytically by using a polytropic model as a modification of the ideal adiabatic analysis. The findings were confirmed by also simulating the proposed alphagamma® configuration in a Sage model which was validated against experimental data with very good agreement. The results of both methods show that the counter-productive compression work can be reduced to almost zero – which makes the compression piston a displacer and explains the name alphagamma® – with the expansion work also reduced for the same net work output. As a consequence, the forces on the pistons, and thus, on the bearings can be significantly reduced, also leading to smaller piston side-loads, less friction and wear. The combination of all advantages allows the design of a mechanically sound and inexpensive machine.

Analysis of Screw-Expander Performance

1989 ◽  
Vol 203 (1) ◽  
pp. 15-20 ◽  
Author(s):  
K C Ng ◽  
T B Lim ◽  
T Y Bong
Keyword(s):  
Experimental Data ◽  
Experimental Work ◽  
Empirical Model ◽  
Saturated Steam ◽  
Polytropic Index ◽  
Work Output ◽  
Predicted Values ◽  
Good Agreement ◽  
Thermodynamic Processes

The paper examines the thermodynamic processes of a helical screw-expander that operates with dry saturated steam at its inlet. The work output of the screw-expander is analysed using a simple ‘pseudo-polytropic’ index. Using the available experimental data from the literature, an empirical model for the prediction of work using the ‘pseudo-polytropic’ indices is formulated. The expansion indices are expressed in terms of built-in volumetric and pressure ratios; how they are formulated is usually given in an expander specification. Based on the empirical model, there is a good agreement between the experimental work and the predicted values.

scholarly journals Modelling of a low-temperature differential Stirling engine

2007 ◽  
Vol 221 (8) ◽  
pp. 927-943 ◽  
Author(s):  
A Robson ◽  
T Grassie ◽  
J Kubie
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Low Temperature ◽  
First Principles ◽  
Dynamic Behaviour ◽  
Stirling Engine ◽  
Current Paper ◽  
Temperature Differential ◽  
Good Agreement

A full theoretical model of a low-temperature differential Stirling engine is developed in the current paper. The model, which starts from the first principles, gives a full differential description of the major components of the engine: the behaviour of the gas in the expansion and the compression spaces; the behaviour of the gas in the regenerator; the dynamic behaviour of the displacer; and the power piston/flywheel assembly. A small fully instrumented engine is used to validate the model. The theoretical model is in good agreement with the experimental data, and describes well all features exhibited by the engine.

scholarly journals Thermodynamic Model for Performance Analysis of a Stirling Engine Prototype

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2655 ◽  
Author(s):  
Miguel Torres García ◽  
Elisa Carvajal Trujillo ◽  
José Vélez Godiño ◽  
David Sánchez Martínez
Keyword(s):  
Heat Transfer ◽  
Decision Making ◽  
Stirling Engine ◽  
Decision Making Process ◽  
Actual Behavior ◽  
Isothermal Model ◽  
Working Cycle ◽  
Stirling Engines ◽  
Expected Values ◽  
The Ideal

In this study, the results of simulations generated from different thermodynamic models of Stirling engines are compared, including characterizations of both instantaneous and indicated operative parameters. The aim was to develop a tool to guide the decision-making process regarding the optimization of both the performance and reliability of Stirling engines, such as the 2.9 kW GENOA 03 unit—the focus of this work. The behavior of the engine is characterized using two different approaches: an ideal isothermal model, the simplest of those available, and analysis using the ideal adiabatic model, which is more complex than the first. Some of the results obtained with the referred ideal models deviated considerably from the expected values, particularly in terms of thermal efficiency, so a set of modifications to the ideal adiabatic model are proposed. These modifications, mainly related to both heat transfer and fluid friction phenomena, are intended to overcome the limitations due to the idealization of the engine working cycle, and are expected to generate results closer to the actual behavior of the Stirling engine, despite the increase in the complexity derived from the modelling and simulation processes.

Preliminary Design and Adiabatic Analysis of a 3kW Free Piston Stirling Engine

2013 ◽  
Vol 325-326 ◽  
pp. 277-282 ◽  
Author(s):  
Chen Duan ◽  
Shui Ming Shu ◽  
Guo Zhong Ding ◽  
Ji Wei Yan
Keyword(s):  
Thermodynamic Analysis ◽  
Stirling Engine ◽  
Preliminary Design ◽  
Free Piston ◽  
Stirling Engines ◽  
Chp System ◽  
Free Piston Stirling Engine ◽  
The Ideal

In recent years, as one kind of Stirling engines, free piston Stirling engines are attracting world attention. Free piston Stirling engines could be applied to the solar dish system, micro-CHP system and so on. The development of a free piston Stirling engine is discussed in this paper. The ideal adiabatic model is used in the preliminary design of the free piston Stirling engine. The key parameters of the designed engine and the thermodynamic analysis are described in detail. Then the performance of the engine is obtained.

scholarly journals Cyclic Control Optimization Algorithm for Stirling Engines

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 873
Author(s):  
Raphael Paul ◽  
Karl Heinz Hoffmann
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Limit Cycles ◽  
Stirling Engine ◽  
Maximum Power ◽  
Maximum Efficiency ◽  
Engine Model ◽  
Stirling Engines ◽  
The Ideal

The ideal Stirling cycle describes a specific way to operate an equilibrium Stirling engine. This cycle consists of two isothermal and two isochoric strokes. For non-equilibrium Stirling engines, which may feature various irreversibilities and whose dynamics is characterized by a set of coupled ordinary differential equations, a control strategy that is based on the ideal cycle will not necessarily yield the best performance—for example, it will not generally lead to maximum power. In this paper, we present a method to optimize the engine’s piston paths for different objectives; in particular, power and efficiency. Here, the focus is on an indirect iterative gradient algorithm that we use to solve the cyclic optimal control problem. The cyclic optimal control problem leads to a Hamiltonian system that features a symmetry between its state and costate subproblems. The symmetry manifests itself in the existence of mutually related attractive and repulsive limit cycles. Our algorithm exploits these limit cycles to solve the state and costate problems with periodic boundary conditions. A description of the algorithm is provided and it is explained how the control can be embedded in the system dynamics. Moreover, the optimization results obtained for an exemplary Stirling engine model are discussed. For this Stirling engine model, a comparison of the optimized piston paths against harmonic piston paths shows significant gains in both power and efficiency. At the maximum power point, the relative power gain due to the power-optimal control is ca. 28%, whereas the relative efficiency gain due to the efficiency-optimal control at the maximum efficiency point is ca. 10%.

scholarly journals Analisa Isolasi Pipa Generator Mesin Stirling Tipe Alpha Sudut Fasa 180°

2021 ◽  
Vol 6 (1) ◽  
pp. 1-7
Author(s):  
Dhimas Satria ◽  
Rina Lusiani ◽  
Erny Listijorini ◽  
Aswata
Keyword(s):  
Heat Loss ◽  
Phase Angle ◽  
Stirling Engine ◽  
Compression Process ◽  
Stirling Cycle ◽  
Compression Speed ◽  
Stirling Engines ◽  
Pipe Insulation ◽  
Alpha Type ◽  
The Ideal

This research is a development of previous research, where in the previous research, a design innovation was carried out on an alpha-type stirling engine by making the phase angle to 180o, with the aim of reducing the effect when the cold cylinder is compressed, because the phase angle currently used is (90o) with disadvantages, namely the cold cylinder is perpendicular to the top, so that the compression process against gravity. But in previous studies, the generator pipe was too long, causing a lot of energy or heat loss (heat loss) so that the compression speed was small. So that in the research, innovated and analyzed the pipe insulation of alpha-type stirling engine generators, alpha-type stirling engines, 180o phase angle. The research method used is to use the thermodynamic approach with Schmidt theory and the theory of the ideal cycle stirling engine. while the simulation is done using the Ideal Stirling Cycle Calculator. Results investigated shows that providing insulation on the generator pipes of an alpha-type stirling engine for an alpha-type stirling engine with a 180o phase angle is proven to reduce a lot of energy or heat loss (heat loss) due to too long generator pipes, with a heat loss value ratio of 226.66 W for the pipe. generator that uses insulation whose value is smaller than the value of the heat loss when the generator pipe without using isocation is 1,584.12 W.

scholarly journals Experimental evaluation of piston motion modification to improve the thermodynamic power output of a low temperature gamma Stirling engine

2021 ◽  
Vol 313 ◽  
pp. 04002
Author(s):  
Michael Nicol-Seto ◽  
David Nobes
Keyword(s):  
Low Temperature ◽  
Power Output ◽  
Stirling Engine ◽  
Maximum Power ◽  
Piston Motion ◽  
Heat Engines ◽  
Stirling Engines ◽  
Thermodynamic Performance ◽  
Engine Power ◽  
The Ideal

Stirling engines are a variety of heat engines which are capable of using heat from various sources including low temperature renewables. This work examines performance of a lab scale low temperature gamma type Stirling engine with a drive train modified with oval elliptical gears. The gears were added to dwell the engine piston motion to attempt to improve the thermodynamic performance of the engine by better replicating the ideal Stirling cycle. A variety of dwelling piston configurations were tested on both the displacer and power piston. It was observed that that the piston dwelling had the anticipated effect of changing the engine indicator diagrams to more closely resemble the ideal cycle, however there were no substantial improvements to maximum engine power. It was observed that dwelling the displacer piston caused substantial reductions to engine running speeds and resulted in maximum power being reduced. In the case of power piston dwelling the indicator diagram was enlarged and there were slight increases to maximum power production. Overall the added complexity of dwelled piston motion systems is not likely an advantageous method of increasing the power output of low temperature difference Stirling engines.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

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