Design measures for organizing laser mirror cooling systems


Аuthors

Leonov E. V.*, Shanin Y. I.**

NII NPO "LUCH", Podolsk, Russia

*e-mail: leonovev@sialuch.ru
**e-mail: ShaninYuI@sialuch.ru

Abstract

Some options for organizing flow channel, waffle, multistorey cooling systems (CS) are considered in order to create the most favorable operating modes of cooled laser mirrors. Several methods of struc-tural impact (hydraulic profiling) on the channel CS in the axisymmetric design of a round mirror are considered to obtain a constant: 1) flow through the channels, 2) Reynolds number, 3) effective heat transfer coefficient, 4) heat insulation coefficient of the mirror base. Using the electrothermal analogy method, it is shown in which places of the channel it is necessary to install heat dissipation intensifi-ers. The approach to profiling of overflow cooling systems with porous inserts (matrices) is described. Flow equalization in porous matrices is carried out by changing the geometric dimensions of the col-lectors, i.e. hydraulic profiling. Improved distribution can be achieved both by varying the porosity of the matrix along the height and length, and by local throttling, for example, by placing an obstacle of a certain height in front of the collector on the side of the main part of the structure or on the side of the heat loaded substrate. The results of the assessments and studies made it possible to propose a number of design solutions for CS for mirrors with coolant flow.
The use of multistorey CSs is caused by the following aspirations: to increase effective heat transfer, to reduce the temperature of the main supporting structure. The study of multistorey systems was car-ried out both experimentally using thermal modeling and on layouts, and analytically. A number of mode-ling experiments were carried out to identify the effect of heat exchange intensity in the floors on the temperature field, as well as a study of the effect of various floor materials. Also, numerical evaluations of operability of deformable adaptive mirrors with mini-channel (hydraulic diameter 0,1–0,2 mm) multistorey CSs were carried out.
In the process of work, the following were carried out: 1) simulations by the method of electrothermal analogy, 2) analytical and 3) experimental studies of models of cooling systems for laser mirrors. Re-commendations on design solutions of laser mirror cooling systems for both passive metal optics and deformable mirrors of adaptive optics are given.

Keywords:

laser mirror, cooling system (CS), hydraulic resistance, heat transfer intensification, multistorey cooling system, intensification coefficient, heat insulation coefficient

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