Analysis of air jets velocity attenuation at special initial conditions

Abstract

The article is devoted to solving the significant problem of efficiency increasing of air distribution in the premise by swirl air jet. The aim of the article is to decrease coefficient of velocity attenuation due to intensification of initial turbulence of different air streams leakage from the air distributor and to obtain of analytical equations for calculation of air distribution in a room to ensure the normative indoor air parameters. Effect of flow twisting results in a reduction of the velocity attenuation coefficient by 2.4 times. The regression analysis testified that the attenuation coefficient of the swirl air jet is more affected by the angle of the twisting plates inclination and less affected by the angle of change of the air flow direction. The attenuation coefficient of all types of rectangular air jets is more influenced by the the ratio of the sides of slit b/l and the angle of change of the air flow direction is also less affected. To minimize the attenuation factor, it is effective to use air distributors at smaller swivel plates inclination angles for swirl air jets and a smaller slit size ratio for all types of rectangular air jets.

Analysis of critical radius of insulation for horizontal pipes

“…In these conditions, the device will be protected against solar radiation cheaper than using green roofs or terraces [25][26]. In addition, air distribution is very important in energy performance [27][28][29][30][31]. The importance rises at variable air volume ventilation [32][33][34][35][36][37].…”

Aerodynamic Characteristics of Different Heights Buildings in Close Proximity

“…The matrix of a two-factor experiment with the effect of the interaction of the determining factors on three levels is presented in Table 1. In the planning matrix (Table 1), x0 is a fictitious dimensionless factor that is only at the upper level (+) ensuring the property of symmetry [37]. Other ones x1 and x2 are dimensionless factors that are at the lower (-) and upper (+) levels, because this is planning of a full factorial experiment of 2 k type [37].…”

“…In the planning matrix (Table 1), x0 is a fictitious dimensionless factor that is only at the upper level (+) ensuring the property of symmetry [37]. Other ones x1 and x2 are dimensionless factors that are at the lower (-) and upper (+) levels, because this is planning of a full factorial experiment of 2 k type [37]. It should be noted that the experiment planning matrix (Table 1) satisfies the following properties:…”