What is Lockhart Martinelli correlation?
The Lockhart–Martinelli correlation for dispersed flow requires the calculation of a two-phase flow modulus Φ to be used in conjunction with either the liquid–phase pressure drop or the gas-phase pressure drop to calculate the two-phase pressure drop in a pipe; that is, (4-268)
How do you calculate the pressure drop of a two-phase flow?
TWO-PHASE FLOW PRESSURE DROP (GAS–LIQUID) ESTIMATION. ΔPL = Pressure drop of liquid phase only (psi/element). ΔPG = Pressure drop of gas phase only (psi/element). The two–phase pressure drop is obtained by multiplying either the liquid–phase drop by φ2L or the gas-phase pressure drop by ϕ2G.
What is two-phase pressure drop?
Pressure drop in two-phase flow is a major design variable, governing the pumping power required to transport two-phase fluids and also governing the recirculation rate in natural circulation systems. The conservation equations for two-phase flow are a subset of those for Multiphase Flow.
What is acceleration pressure drop in two-phase flow?
The total two-phase flow pressure drop consists of two components: an acceleration component and a fictional component. The accelerational pressure drop component results from acceleration of the flow during the evaporation process. It was evaluated and shown to be small relative to the frictional component.
What is two-phase flow pipe?
Two-phase flow refers to the interactive flow of two distinct phases with common interfaces in a channel, with each phase representing a mass or volume of matter. The two phases can exist as combinations of solid, gas and/or liquid phases.
What is acceleration pressure drop?
The total acceleration pressure drop is defined by measuring the pressure difference between two points at the acceleration zone. The pressure drop of steady state flow for the same length is then reduced from the previous measurement to find acceleration only energy loss.
What is slug flow in piping?
The word slug usually refers to the heavier, slower moving fluid, but can also be used to refer to the bubbles of the lighter fluid. This flow is characterised by the intermittent sequence of liquid slugs followed by longer gas bubbles flowing through a pipe.
What is bubbly flow?
General Description. Bubble flow is defined as a Two-Phase Flow where small bubbles are dispersed or suspended as discrete substances in a liquid continuum.
What is acceleration pressure?
How do you stop slugs from flowing in pipes?
Slug flow can be avoided in process piping by [56]: Using a low point effluent drain or bypass. Reducing line sizes to the minimum permitted by available pressure drops. Arranging the pipe configuration to protect against slug flow.
Why slug flow is undesirable?
Severe slug flow is one of the most undesired multiphase flow regimes, due to the associated instability, which imposes major challenges to flow assurance in the oil and gas industry.
What is the Lockhart-Martinelli correlation?
Lockhart-Martinelli correlation. The method of Lockhart and Martinelli is the separated flows method that predicted the two-phase frictional pressure drop.
What is Lockhart Martinelli’s (LM) parameter?
Lockhart Martinelli’s parameter (X) is used to calculate pressure drop for two phase flow in pipes. The Lockhart Martinelli’s (LM) parameter is calculated as a square root of the ratio of pressure drop when only liquid flows to the pressure drop when only gas (or vapor) flows. This definition was seen earlier.
Which method of Lockhart and Martinelli predicted the two phase frictional pressure drop?
The method of Lockhart and Martinelli is the separated flows method that predicted the two-phase frictional pressure drop. Thermal Engineering An alternate approach to calculate two-phase pressure drop is the separated-phases model.
What is Martinelli parameter in flow cytometry?
Parameter X, the Martinelli parameter, is a ratio of pressure drops of single-phase flow terms. As can be seen from eqs. (11.79) – (11.82), the pressure drop in two-phase flow can be determined if any one of the four multipliers is known.