Modelling of Convective Heat and Mass Transfer in Rotating Flows by Igor V. Shevchuk

Author:Igor V. Shevchuk
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

In the unshrouded cavity (Fig. 4.19), experiments [55] revealed air ingress from the atmosphere near the center plane of the gap (z = s/2), which causes the mass flow rate in the boundary layers near the periphery to increase with the coordinate r (instead of being constant as in the Ekman-type layers). This entails a decrease in the swirl parameter β not modeled by the present integral method. Curve 4 for and 6173 correlates fairly well with the experiments [55] up to the point of the maximum of β. Lines A for C w = 1111 exhibit a reduced accuracy, because the flow near the radial location r/r i = 2.1 is transitional, which is not properly captured by the present integral method [55].

A perforated shroud at the periphery prevents the air ingress from the atmosphere. Curves 4 and 5 in Fig. 4.20 obtained with the present integral method agree well with the experiments [2]. With an increase in the Reynolds number or r/b, turbulence becomes fully developed, which improves the agreement with the experiments. Curves for n = 1/7 and n = 1/9 lie close to each other.

Fig. 4.20Local swirl parameter β in a cavity with a perforated shroud at C w = 2500, β i = 1, s/b = 0.1, and r i/b = 0.1 [6]. 1–3—Experiments [3]. Present integral method: 4—n = 1/7 [71]; 5—1/9. Lines 6—Ekman-type layer model (4.104), n = 1/7; lines 7—Eq. (4.105) [4]. Lines A and experiments 1—Re φ = 1.1 × 106; B and 2—6.177 × 105; C and 3—5.47 × 105

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