Experimental Study of the Operation Conditions of Stability on a Gamma Stirling Engine

Author(s):  
Houda Hachem ◽  
Ramla Gheith ◽  
Fethi Aloui ◽  
Sassi Ben Nasrallah

Considering Stirling engines modern applications and cogeneration recovery energy from industrial process, the power of a Stirling prime mover is to be provided at a speed of rotation adapted to the operation of the receiver system (usually a generator) to exploit the performance of this machine under the conditions of its use (ie lowering of the rotational speed and torque transmitted rise or, more rarely, elevated speed and lowering the torque transmitted). Knowing that the hot air engine cannot change speed quickly and in order to have a well designed system, it is important to study the unsteady state conditions. In this work we present an experimental stability analysis of an irreversible heat engine working at different conditions. The experimental study aims at analyzing the effect of working parameters disruption on the stability of the Gamma Stirling engine. Parameters involved in this experimental study are the load pressure of the motor and the load applied to the Stirling engine. The influence of engine operating parameters on its torque and rotational speed is investigated. The time required by a gamma type Stirling engine to stabilize operation after disruption is estimated. Results show that after a small disruption, speed and temperature evolutions decays exponentially to the steady state determined by a relaxation time. It is assumed that the decrease of the applied power load to the engine or the increase of the load pressure leads to a speed up. And that the increase of the applied power load to the engine or the decrease of the load pressure leads to a speed down.

2020 ◽  
Vol 20 (5) ◽  
pp. 113-122
Author(s):  
Jiman Lee ◽  
Semyeoung Lee

Because fire in a traditional market spreads very fast, it is necessary to install an alarm system that can detect the fire early and identify the exact ignition point. The addressable detector can be used to identify the ignition point quickly using the address function. In this study, an existing general-type detector installed in a traditional market was replaced with an addressable detector, and firefighters measured the time taken to reach the initial ignition point. From the experimental results, the average time taken from DaeSin 119 Safety Center to reach the virtual ignition point on the 2<sup>nd</sup> floor of the 2<sup>nd</sup> district of Seomun Market was 3 min 12 s when the <general-type detector-P-type receiver> system was applied. However, the time was 2 min 8 s when the <addressable-type detector-R-type receiver>system was applied. Based on the experimental investigation, it was confirmed that the time required for firefighters to reach the initial ignition point decreased when the existing general-type detector was replaced with the addressable detector.


2020 ◽  
Vol 35 (3) ◽  
pp. 464-470 ◽  
Author(s):  
Wenjie Zhao ◽  
Junfei Wu ◽  
Fushan Chen

AbstractThe fundamental reason for the environmental pollution caused by the papermaking industry is the inadequate treatment of the black liquor. How to dispose of the lignin macromolecules, which is the main pollutants in the black liquor, is the key to addressing the environmental pollution. At present, cross-flow membrane filtration is one of the effective ways to retain and recycle lignin macromolecules in black liquor. The paper proposes the adoption of a dynamic blade cross-flow membrane filtration equipment provided by German BOKELA company to treat papermaking black liquor. The experiment shows that when the black liquor is treated with dynamic blade rotation cross-flow, the membrane with a molecular weight cut-off of nanofiltration (NP010) delivers the best retaining effect, with 28 % more lignin in black liquor than that in untreated black liquor. Meanwhile, when the blade rotational speed reaches 300 rpm and the transmembrane pressure is 0.5 or 2 bar, the flux of black liquor through nanofiltration NP010 is relatively desirable.


1963 ◽  
Vol 18 (5) ◽  
pp. 1041-1042 ◽  
Author(s):  
Curt A. Wiederhielm

A system which permits continuous recording of dimensions of microscopic blood vessels is described. The system utilizes information contained in the video signal of a television microscope to develop an analog voltage proportional to the time required for the electron beam to sweep across the image of the blood vessel. This time interval is also proportional to the dimension of the vessel. Calibration of the system yielded a standard error of estimate of ±3.7 μ on a series of glass capillaries, ranging in size from 15 to 150 μ. The rise time of the system was in the order of 40 msec. Long- and short-term drift was less than 3 μ/hr. The system is used in an experimental study of viscoelastic properties of small arteries and arterioles. microcirculation; viscoelastic properties; frog mesentery Submitted on April 17, 1963


2010 ◽  
Vol 426-427 ◽  
pp. 658-663 ◽  
Author(s):  
Min Kang ◽  
X.Q. Fu ◽  
Yong Yang

In order to machine revolving workpieces which are made of difficult-to-cut materials or have low rigidity, the technology of Numerical Controlled Electrochemical Turning (NC-ECT) was put forward and the preliminary experimental study was presented in this paper. To carry out the study, an experimental setup was developed, and a new special kind of inner-spraying cathode with single linear edge was designed according to the process of machining cylindrical surface and the requirement of stable electrolyte flow field. First, the NC-ECT method was simply described. Then, considering the structure of the cathode and the machining process, the method for calculating the material removed depth per revolution in machining the cylindrical surface was given. Finally, the experiments of machining the cylindrical surface were carried out. Experiments showed: 1) The calculated material removed depth per revolution is well consistent with the actual value of the machining process, which decreases with the increase of the rotational speed of the workpiece and increases almost linearly with the increase of the working voltage; 2) The surface roughness decreases with the increase of the rotational speed of the workpiece and the working voltage; 3) The working current in the machining process trend to stable after several revolutions.


2017 ◽  
Vol 18 (3) ◽  
pp. 305 ◽  
Author(s):  
N. Martaj ◽  
R. Bennacer ◽  
L. Grosu ◽  
S. Savarese ◽  
A. Laaouatni

1991 ◽  
Vol 113 (3) ◽  
pp. 604-611 ◽  
Author(s):  
C. Y. Soong ◽  
S. T. Lin ◽  
G. J. Hwang

The paper presents an experimental study of convective heat transfer in radially rotating isothermal rectangular ducts with various height and width aspect ratios. The convective heat transfer is affected by secondary flows resulting from Coriolis force and the buoyancy flow, which is in turn due to the centrifugal force in the duct. The growth and strength of the secondary flow depend on the rotational Reynolds number; the effect of the buoyancy flow is characterized by the rotational Rayleigh number. The aspect ratio of the duct may affect the secondary flow and the buoyancy flow, and therefore is also a critical parameter in the heat transfer mechanism. In the present work the effects of the main flow, the rotational speed, and the aspect ratio γ on heat transfer are subjects of major interest. Ducts of aspect ratios γ=5, 2, 1, 0.5, and 0.2 at rotational speed up to 3000 rpm are studied. The main flow Reynolds number ranges from 700 to 20,000 to cover the laminar, transitional, and turbulent flow regimes in the duct flow. Test data and discussion are presented.


Author(s):  
Hwabhin Kwon ◽  
Heesung Park

Abstract A turboexpander for the propane de-hydrogenation process with blade and splitter has been numerically investigated. Since the turboexpander expands fluid from higher inlet pressure to lower discharge pressure, the kinetic energy of fluid is converted into useful mechanical energy. The efficiency and power generation with the designed turboexpander have been simulated with different operating conditions. The pressure ratio between inlet and outlet and rotational speed are varied to characterize the performance of the turboexpander as an electrical power generator. The numerical simulations have shown the vortex at the trailing edges of blade and splitter which decreases the efficiency. The rotational speed and the pressure ratio are parameterized to obtain operation conditions which achieve high power generation and efficiency. Consequently, the generated power from 614.12 kW to 693.45kW is obtained at the normal rotational speed and the pressure ratio between 1.75 to 2.22.


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