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• Hydrocarbon mixtures condensation flow was investigated at heaving condition. • The simulation results coincided to experimental ones with ±15% error. • The impacts of various parameters on pressure drop and heat transfer were discussed. • Methane/ethane mixture had the best heat transfer and the smallest pressure drop. • It showed better performance at heaving condition than static one. A model based on ASNYS CFX was established to explore the pressure drop and heat transfer characteristics of condensation flow with hydrocarbon mixtures in a spiral pipe under static and heaving conditions, whose deviations are within ±15% compared to experimental ones. It considered the effects of motion parameters, operating parameters and structural parameters on frictional pressure drop and heat transfer coefficient for three hydrocarbon mixtures. The ranges of mass flux, vapor quality, heat flux, saturation pressure, hydraulic diameter, curvature diameter and inclination angle were 200–800 kg/(m2·s), 0.3–0.9, 10–20 kW/m2, 2–4 MPa, 6–14 mm, 1.6–2.4 m and 6–14°, respectively. The results demonstrate that methane/ethane mixture has the best heat transfer and the smallest pressure drop among three mixtures. At static condition, as the vapor quality and mass flux increase and the saturation pressure and hydraulic diameter decrease, there are evident increases in heat transfer and pressure drop, whereas the impacts of curvature diameter, inclination angle and heat flux on them are insignificant. Meanwhile, the heaving motion affects pressure drop and heat transfer and makes it show better overall heat transfer performances, where the comprehensive heat transfer factors (CHFs) of 83.33% data points are more than 1. Further, the heaving effects increase with the increasing heaving amplitude and the decreasing heaving cycle. [ABSTRACT FROM AUTHOR]

Highlights • A model was established to investigate condensation flow under sloshing condition. • The influence of different parameters on pressure drop and heat transfer was studied. • The comprehensive effects of sloshing conditions were analyzed. • Sloshing conditions little affect pressure drop, but obviously affect heat transfer. • The heaving condition has the maximum effects on flow and heat transfer among others. Abstract In order to explore condensation flow and heat transfer characteristics in the tube side of spiral wound heat exchange (SWHE) used in floating liquefied natural gas (FLNG) field, a model was established to simulate methane condensation upward flow in a spiral pipe at different sloshing conditions, such as heave, roll and pitch conditions. The simulated results coincide with experiment ones, and the deviations are within ±15%. The effects of various parameters on frictional pressure drop and heat transfer coefficient were discussed in pipes with curvature ratio of 0.003–0.007. The ranges of Reynolds numbers in vapor and liquid flows are respectively 154,944–697,251 and 18,190–127,331. It was found that at static conditions, both frictional pressure drop and heat transfer coefficient increase with the increase of mass flux and the decrease of saturation pressure and hydraulic diameter; with the increase of vapor quality, the heat transfer coefficient first increases and then decreases whereas the frictional pressure drop continuously increases; the effects of curvature diameter are slight. Meanwhile, in most cases, the sloshing motions can cause a remarkable heat transfer enhancement as well as a small decrease of frictional pressure drop. Further, the effects of heaving motion on flow and heat transfer are more obvious than the others, with the average drag reduction and heat transfer augmentation of 1.51% and 15.70%, respectively. These results are helpful for the understanding condensation characteristics in the spiral pipe at sloshing conditions, and for the design of SWHE used in FLNG field. [ABSTRACT FROM AUTHOR]

In this paper, the condensation heat transfer of hydrocarbon mixtures refrigerant (methane/propane) flowing in a helical tube with 10 mm hydraulic diameter was investigated by experiments and numerical simulations. The experiments were conducted at mass flux of 200–400 kg/(m 2 ·s), saturation pressure of 0–4Mpa and heat flux of 4.8–5 kW/m 2 . Also, the effects of mass flux, vapor quality, and saturation pressure on heat transfer coefficient were studied. It was observed that the heat transfer coefficients increased with the increase of mass flux and vapor quality, while the heat transfer coefficients generally decreased as the saturation pressure increased. Meanwhile, annular flow(half-annular flow, annular flow) and Non-annular flow patterns (slug flow, stratified flow, wavy flow, transition flow) were observed during the condensation of methane/propane mixtures refrigerant. And a new flow pattern transition line for hydrocarbon refrigerants condensation process was proposed. The condensation heat transfer coefficient data were compared with several existing correlations, and a modified heat transfer correlation for different flow patterns was proposed, which predicted the results well with a mean absolute error of 10.03%. [ABSTRACT FROM AUTHOR]

Helical tube has been widely used in liquefied natural gas (LNG) liquefying applications. However, studies on the heat transfer performance of hydrocarbon mixture refrigerant in a helical tube have rarely been conducted. In this paper, condensation heat transfer characteristics of hydrocarbon mixture refrigerant in a helical tube were investigated numerically. The tests were conducted at saturation pressure of 2–4 MPa, mass flux of 100–400 kg/(m 2 ·s) and vapor quality 0–1. The numerical model was well verified by experimental data. And the effects of different structural parameters (tube diameter, helix angle and curvature diameter) and operating parameters (mass flux, heat flux and saturation pressure) on the heat transfer of hydrocarbons refrigeration were considered. The results showed that the tube diameter and mass flux had significant effect on condensation heat transfer coefficient. Meanwhile, stratified flow, half-annular flow and annular flow were observed during the condensation of methane/propane mixtures refrigerant by simulations, and a new flow pattern transition line for hydrocarbon refrigerants condensation process was proposed. Finally, the simulation results were compared with several well-known condensation heat transfer correlations. The research results will provide some constructive instructions for more effective design of LNG heat exchanger. [ABSTRACT FROM AUTHOR]