Virtual accelerometer for sensorless overstroking control in a linear compressor of a cryogenic cooler

Author(s):  
Alexander Veprik ◽  
Herman Vilenchik ◽  
Nachman Pundak
2009 ◽  
Author(s):  
V. Maron ◽  
A. Veprik ◽  
L. Finkelstein ◽  
H. Vilenchik ◽  
I. Ziv ◽  
...  

2000 ◽  
Vol 7 (6) ◽  
pp. 363-379 ◽  
Author(s):  
A.M. Veprik ◽  
V.I. Babitsky ◽  
N. Pundak ◽  
S.V. Riabzev

Modern infrared imagers often rely on the split Stirling cryogenic coolers the linear compressors of which are the well-known sources of harmonic disturbance. The traditional method of their passive isolation fails to meet the restraints on the static and dynamic deflections which are originated by the combined action of the airborne g-loading and harsh random vibration.The vibration protection system, which combines a stiff and heavily damped vibration isolator with tuned dynamic absorber, is studied and optimised for use in the design of an airborne infrared device.Such a design is aimed, primarily, at essential dynamic suppression of the harmonic force which is produced by the linear compressor and, secondarily, at minimisation of environmental vibration loads transmitted through the infrared device to the linear compressor. Experimental testing backed up the theoretical results.


Cryogenics ◽  
2009 ◽  
Vol 49 (5) ◽  
pp. 165-170 ◽  
Author(s):  
A. Veprik ◽  
I. Nachman ◽  
N. Pundak

Author(s):  
Lei Ding ◽  
Hua Zhang ◽  
Shaoshuai Liu ◽  
Zhenhua Jiang ◽  
Haifeng Zhu ◽  
...  

Author(s):  
Domenico Borello ◽  
Giovanni Delibra ◽  
Franco Rispoli

In this paper we present an innovative Partially Averaged Navier Stokes (PANS) approach for the simulation of turbomachinery flows. The elliptic relaxation k-ε-ζ-f model was used as baseline Unsteady Reynolds Averaged Navier Stokes (URANS) model for the derivation of the PANS formulation. The well established T-FlowS unstructured finite volume in-house code was used for the computations. A preliminary assessment of the developed formulation was carried out on a 2D hill flow that represents a very demanding test case for turbulence models. The turbomachinery flow here investigated reproduces the experimental campaign carried out at Virginia Tech on a linear compressor cascade with tip leakage. Their measurements were used for comparisons with numerical results. The predictive capabilities of the model were assessed through the analysis of the flow field. Then an investigation of the blade passage, where experiments were not available, was carried out to detect the main loss sources.


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