Showing papers by "Sreenivas Jayanti published in 1990"
TL;DR: In this article, the structure of the liquid film in horizontal annular flow is studied visually using the refractive index matching technique, and a new conceptual picture of the gas-liquid interface is presented.
73 citations
TL;DR: In this article, the authors investigated the time-dependent behaviour of the liquid film in horizontal annular two-phase flow and proposed a new mechanism based on the shape of disturbance waves.
69 citations
TL;DR: In this paper, the authors classified the dryout data into three groups: stratification-, redeposition-dominated and entrainment-dominated dryout, and developed transition criteria for these zones in a dryout map.
61 citations
TL;DR: In this article, the authors used wall functions to account for wall roughness, and verified this approach to compare their predictions with the data of Nikuradse and Hanjalic & Launder.
Abstract: It is widely believed that the secondary flow mechanism, namely the generation of secondary flow in the gas phase due to circumferentially varying interfacial roughness, plays an important role in the liquid film distribution in horizontal annular flow. We study this mechanism numerically using the HARWELLFLOW 3D computer program. We use wall functions to account for wall roughness, and verify this approach to comparing our predictions with the data of Nikuradse and Hanjalic & Launder. We then apply the methodology to the prediction of secondary flow in a pipe subjected to differential wall roughness, and show that the contribution of the secondary flow in the gas is hitherto overestimated by up to an order of magnitude.
29 citations
TL;DR: In this paper, the results obtained at the CEN-Grenoble with a freon-12 loop with electrical heating were analyzed qualitatively, and a first attempt at correlating the results was presented.
19 citations
TL;DR: In this paper, a single-phase flow in curved ducts is numerically simulated by imposing a spatially varying centrifugal force on a fluid flowing in a straight tube, and a set of partial differential equations is solved using the HARWELL-FLOW3D computer program.
Abstract: SUMMARY The advent of standard algorithms for the numerical solution of partial differential equations has given researchers a new tool for fluid flow calculations. In this paper, single-phase flow in curved ducts is numerically simulated by imposing a spatially varying centrifugal force on a fluid flowing in a straight tube. The resulting set of partial differential equations is solved using the HARWELL-FLOW3D computer program. Comparison with other numerical and experimental results shows that this simplified formulation gives accurate results. The model neglects certain geometric terms of the order d/D, the duct-to-coil diameter ratio. The effect of these terms is investigated by considering the flow in a 90" bend for large d/D. It is shown that while there may be significant error in the prediction of the local variables for large d/D, the circumference-averaged quantities are well predicted.
10 citations