The effect of the flow direction inside the header on two-phase flow distribution in parallel vertical channels

Effect of flow direction for flow and heat transfer characteristics in outward convex asymmetrical corrugated tubes

“…A new kind outward convex asymmetrical corrugated tube (ACT) has been recently studied, which improves the overall heat transfer performance [21]. The effect of fluid flow directions for the asymmetrical components of heat exchangers is a significant factor considered in many research works due to its evident affection on the heat transfer performance, such as the transverse and longitudinal direction of serrated fins [22], the counterflow and parallel flow of plate-fin heat exchanger [23], the main flow direction inside the header [24]. However, for ACT, quite few numerical reports can be found for its opposite fluid flow directions and heat transfer problems.…”

Numerical model of two-phase refrigerant flow distribution in a plate evaporator with distributors

“…The influencing factors for flow maldistribution in PHEs were experimentally analyzed, including the mass flow rates of cold fluid and two-phase fluid, the flow configuration, the number of channels, the header geometry and the flow direction [4,16e21]. The research results show that, changing the heat load on the evaporator test section has little influence on the two-phase flow distribution, while the two-phase flow distribution markedly influenced the heat transfer between the refrigerant and the counter flowing fluid [16]; the flow maldistribution occurs when the number of channels increases and the nature of the pressure profiles is not the same at different steam exit conditions [17e19]; the application of distributor leads to the decrement of flow maldistribution [20,21]. However, no study has been reported concerning the numerical research on the flow distribution of twophase refrigerant in plate evaporators.…”

CFD initial assessment of a protrusions based experimental facility

“…2. In the first one (hereafter "P3") the protrusion depth has 3 levels: it increases in the flow direction from h/D=0.50 (protrusions 1 and 2), to h/D=0.75 (protrusions 3, 4, 5 and 6), to h/D=0.90 (protrusions 7, 8, 9 and 10), then it symmetrically decreases to h/D=0.75 (protrusions 11, 12, 13 and 14) and to h/D=0.50 (protrusions 15,16). The second configuration (hereafter "P2") has only 2 depths: the protrusion depth is constant (h/D=0.90) except for the first 2 protrusions and the last two (protrusions 15, 16) for witch h/D=0.75.…”

“…The experimental apparatus employed in this study is described in details in some recent papers [15][16][17]. The flow loop consists of a transparent test section and two supply lines of air and water, which converge into a horizontal pipe.…”

“…The aim of an experimental campaign carried out in the past [14][15][16][17][18][19] was therefore to deeply investigate some phenomenological aspects of the two-phase flow separation produced by inserting protrusion tubes inside the header. The parameters of the experimentation were the protrusion depth and the gas and liquid superficial velocities.…”