Thermal hydraulic efficiency of coplanar cooling channels for liquid rocket engine chambers

THERMAL, ELECTRIC JET ENGINES

AND POWER PLANTS OF AIRCRAFTS

THERMAL HYDRAULIC EFFICIENCY OF COPLANAR COOLING

CHANNELS FOR LIQUID ROCKET ENGINE CHAMBERS

V.P. Alexandrenkov

Bauman Moscow State Technical University, Moscow, Russian Federation

e-mail:

The paper considers the coplanar circuits (with cross finning) used for cooling

liquid rocket engines by means of the maximal heat removal criterion. The available

experimental data on the convective component of heat loss are used to perform

computational and analytical analysis of the influence of both thermal hydraulic flow

characteristics and finning parameters on their efficiency. The possibility of using the

proposed methodology for evaluating the heat transfer efficiency in the conventional

finned circuits with regard to the coplanar flow peculiarities is demonstrated. The

domains of finning parameters are defined with a significantly higher (2–4 times)

efficiency in comparison with the conventional finning of the cooling channels.

Keywords

circular coplanar channel, cross-finning, convective heat transfer

intensification, efficiency, maximal heat removal, finning parameters, thermal

hydraulic characteristics.

Cooling channels of liquid rocket engines (LRE) chambers are circular

channels formed by two shells joined with finning. As demonstrated in

[1] the finning factor significantly affects the efficiency of the firewall

cooling. It was also found out that under certain conditions the finning

factor can lead to negative results, i.e. lower heat removal as compared to

the reference smooth channel without heat transfer intensification (HTI).

Therefore, the heat transfer intensification of the convective component is a

critical problem in terms of an additional or countervailing measure, which

can considerably increase the heat removal from the firewall in order to

achieve the required cooling conditions.

Taking into account the finning scale and technological constraints, the

well-known conventional methods of HTI such as “artificial roughness”

are quite limited in use.

The method of heat and mass transfer intensification in the circular

finned channels, so called the vortex or coplanar method, is described

and analyzed in [2, 3]. A coplanar channel (CC) (Fig. 1) is an innovative

structure of joined shells and cross fins on the opposite surfaces of the

circular channel enabling the cross flow of a heat transfer agent.

This design solution is a special type of the classic finned channel with

additional geometric parameters and the obvious specific nature of both

heat and mass transfer mechanisms and their calculation.

The model of physical flow in such a channel is a combination of

individual coplanar vortex flows formed by cross finning due to viscous

ISSN 0236-3941. HERALD of the BMSTU. Series Mechanical Engineering. 2015. No. 2