Liquid Volume Flow Rate Research Articles

Effect of liquid properties on film behavior on the surface of an airfoil in a high-speed flow and subsequent atomization from the trailing edge

This study examines the behavior of ethanol or water films on the surface of a NACA 0012 airfoil placed in a high-speed air flow. New water film results complement previous measurements of time averaged ligament lengths and droplet sizes generated with the same airfoil. In addition, new data are obtained for ethanol. Air velocities up to 175 m/s are used with liquid flow rates between 1.4 cm2/s and 2.6 cm2/s. The liquid was introduced onto one side of the airfoil via 26 holes, each measuring 0.5 mm in diameter and spaced 1 mm apart. These holes are positioned 35 mm downstream from the leading edge and 65 mm upstream from the trailing edge. Film behavior on the vane is captured with front-lit high-speed video. The accumulation of liquid and breakup of ligaments are captured with backlit highspeed video. Phase Doppler interferometry is used to measure droplet size and simultaneous axial and pitch wise velocity 70 mm downstream of the trailing edge. Finally, laser diffraction is used to measure line averaged droplet sizes. The results indicate notable differences between ethanol and water films. The ethanol film spreads more extensively across the width of airfoil which is attributed due to its lower surface tension. The maximum ligament length for both liquids decrease with higher air velocity and increase with the liquid flow rate. A correlation for maximum ligament length is developed and captures the effect of liquid properties, flow rate, and air velocity. Furthermore, the variation in liquid volume flow rate did not impact droplet size. However, for a given air velocity, the Sauter Mean Diameter is found to depend on surface tension. On the dependency of droplet size on the Weber number, ethanol produced smaller droplet sizes at low values of Weber number. However, at relatively high Weber numbers, the droplet sizes for both water and ethanol were similar. This suggests that droplet size is influenced by factors besides surface tension at low Weber numbers but not at higher Weber numbers. In addition, the Nukiyama-Tanasawa model to fit the volume distribution curves is simplified by fixing p and q terms. Simplification makes the model easier to understand and implement.

Exploring the thermal shielding performance by coupling phase change material to liquid cooling plate

To enhance the thermal shielding performance of high-temperature heat source target, an evolved cold shield system coupling phase change material (PCM) and liquid cooling plate with serpentine flow channel is developed. The thermal shielding effectiveness of the proposed system is illustrated by comparing the duration maintained at a lower temperature on the cold surface, and the temperature uniformity of the cold surface is analyzed to describe the role of PCM in the thermal shielding performance. The influences of the operating parameters of the liquid cooling plate and PCM physical parameters on the thermal shielding performance of the heat source targets are investigated. The results indicate that coupling PCM to a liquid cooling plate can effectively improve the thermal shielding performance. Increasing the heat power of the heat source target from 190 W to 231 W will lessen the advantage time from 3090 s to 1980 s for the coupled system. The advantage time is shortened by 1500 s as increasing the liquid volume flow rate from 0.26 L/min to 1.30 L/min. Lifting the starting temperature of the coolant from 15 °C to 25 °C prolongs the advantage time from 2130 s to 3090 s. The advantage time is improved by 660 s as increasing the PCM phase transition temperature from 26 °C to 30 °C, and increasing the PCM covering thickness from 8 mm to 10 mm extends the advantage time from 1830 s to 3090 s. Meanwhile, the temperature equalization of the cold surface for the coupled system is better than the single liquid cooling. These results indicate that the proposed coupled system has potential applications in improving thermal shielding performance as well as heat flow control, thermal insulation, and other areas of heat regulation.

Performance Envelope of a 538-Series High-Speed Helico-Axial Pump for High-Gas-Volume-Fraction Operation

Summary Operating at high speeds can have the benefit of increasing the capability of pumps to enhance surface or downhole production of fluids with high gas volume fraction (GVF). This study presents the performance envelope of a high-speed helico-axial pump (HAP) operating at high GVFs (>80%). The ultimate aim of the physical tests was to ascertain the operating capabilities of the pump for potential scaleup to a field prototype. The HAP housing outer diameter was 5.38 in. and operated at a rotational speed of 6,000 rev/min. Air and water were the test fluids, with an average pump intake and a discharge temperature of 28°C. The fluid volume flow rates were varied while maintaining 46 psig at the HAP intake. The liquid and total intake volume flow rates varied from 128 B/D to 664 B/D and 4,941 B/D to 7,593 B/D, respectively. The corresponding dimensionless pressure boost (DPB), GVF, liquid flow coefficients (LFCs), and total flow coefficients (TFCs) were recorded. Additional parameters noted were the percentage of electric current draw to full-load motor current by the HAP motor and the percentage of electric power input to full load power to the HAP motor. The results showed that the HAP had a stable operation during the tests for intake GVF range of 91–98%. The corresponding pump DPB was in the range of 0.0138–0.0751. These values being positive indicated the capability of the HAP to boost fluid pressure even for such high intake gas content and avoid pump gas lock. The results also showed that for a given intake GVF, the HAP DPB increased with decreasing LFC. For a given LFC, the DPB decreased with increasing intake GVF. The percent electric input power to the HAP motor varied between 28% and 64% of full-load motor power. It was observed to strongly increase with decreasing LFC at a given intake GVF and very strongly decrease with increasing intake GVF at a given LFC. The associated percent electric current draw by the HAP motor was seen to vary between 24% and 53% of full-load motor current. Its variation with LFC and intake GVF was similar to those of the percent electric power input. The DPB, percent electric current, and power draw by the HAP motor variations with TFC for a given intake GVF were similar to those of the LFCs. In conclusion, the HAP demonstrated the capability to boost fluid pressure when handling high GVF flows. It is being scaled up to a field prototype to handle higher volume flow rates of high GVF gas-liquid mixtures. This study mainly highlights the method to extend the gas-handling capability of a HAP by operating it at high speeds. Optimal hydraulic design and proper conditioning of the inlet flow components were also incorporated into the HAP architecture. Expanding the HAP operating envelope to handle high-GVF flows significantly unlocks the potential for field operators to maximize hydrocarbon production from high-gas content applications. This, in turn, increases the economic bottom line from the field asset.

Study on the Solid–Liquid Mass-Transfer Performance of Suspension in a Rotating Packed Bed

This work presents the study on solid–liquid mass-transfer performance of suspension in a rotating packed bed (RPB). The calculation model of solid–liquid mass-transfer coefficient (kS) is deduced on the basis of the mass conversation law. The kS in RPB is measured using the suspension of cation-exchange resin particle reaction with NaOH solution. The effects of different operating conditions such as the dispersion time (t) in a stirred tank reactor (STR), the rotating speed (N), the mesh packing thickness (w), the liquid volume flow rate (LT), and the solid loading (e) on the RPB are investigated. The results show that kS increases with the increase of N and w; it increases first and then tends to remain constant with the increase of t and LT. However, e has little influence on kS. A nondimensional equation for Sh is established, and the predicted and experimental values of Sh are in good agreement with a deviation within ±15%. Furthermore, the maximum value of Sh of 124 is obtained under the conditions, t = 0.5 h in STR, N = 2200 rpm, LT = 56 L/h, e = 15 g/L, and w = 24 mm, which is higher than those in the microreactor (MR) and STR. Here, RPB exhibits great application potential in the solid–liquid mass-transfer or reaction process.

Experiments on Slug Flow Dynamics in Helically Coiled Tubes

Slug flow characteristics in helically coiled tubes were investigated in experiments. Pressure loss, slug velocity, and slug passing frequency were measured using pressure transducers and backlight imaging of dyed water under illumination. For a 20-mm-diameter tube, parametric dependencies on gas and liquid volume flow rates for total superficial velocities of up to 6 m/s with three different radii of curvature (R = 0.270 m, R = 0.375 m, and R = infinity/straight tube) were explored. The main experimental results obtained are (1) the bubbly flow regime shrinks because of centrifugal acceleration from the coiled geometry, (2) the liquid slug length remains unchanged regardless of changes in gas and liquid flow rates, and (3) the pipe friction factor decreases with slug passing frequency.

Optimum design of inline gas-liquid cyclone separator for wide range of inlet gas volume fractions

ABSTRACT The inline gas-liquid cyclone separator has been gradually used in oil & gas industry due to its high separation efficiency and less footprint. However, under the inlet flow conditions with large range of gas volume fractions, the research on structure design and separation performance are seriously insufficient. The preliminary structural design of the inline gas-liquid separator was carried out according to the particle separation theory, and the key structural parameters were optimized by using the Response Surface Method (RSM) together with Computational Fluid Dynamics (CFD). The structure optimization has improved the degassing efficiency by 17.44% and dehydration efficiency by 7.59%. With air and water as working medium, the separation performance of the inline gas-liquid cyclone separator was experimentally investigated in laboratory under a large range of gas volume fractions. The results show that the separation efficiency for both degassing and dehydration can exceed 80% with the inlet gas volume fraction ranges from 0.2 to 0.8. The optimum normalized flow split and liquid volume flow rate are 0.9 –1.2 and 8 m3/h, respectively.

Water Model Experiments on the Influence of Phase Distribution in the Submerged Entry Nozzle Considering Varying Operating Conditions

Continuous casting of steel argon injection into the submerged entry nozzle (SEN) via the stopper is common practice. Nonetheless, the resulting phase distribution in the SEN is still under discussion. The main available casting parameters at the steel plant to determine the flow situation in the SEN are usually the stopper rod position, the argon feeding pressure, the argon flow rate, and the casting speed. To show the potential influence of the phase distribution on the stopper characteristic and on the argon feeding pressure, experiments using a 1:3 scale water model are presented. For the experiment, the water flow rate is scaled using Froude similarity, while the air flow rate is chosen to keep the ratio between the liquid and gas volume flow rate constant. The casting parameters and the pressure at three distinct levels of the SEN are measured. To relate this measurement data to the corresponding phase distribution, two cameras are used to document the phase distribution in the SEN. The images show four major phase distribution patterns. These patterns can be linked to significant changes in the measured pressure levels and the behavior of the stopper.

Specific features of the multiphase fluid subsea pipeline operation at the liquid accumulation mode

The operation modes of an extensional subsea pipeline of multiphase fluid at the initial stage of the offshore gas condensate field development under the conditions of liquid accumulation are studied. By means of the dynamic simulation of the slug flow mode, the frequency and volume of liquid plugs removed from the pipeline are analyzed as a function of the gas flow rate. It is demonstrated that with a decrease of the gas flow rate, the steadystate hydraulic calculations predict significantly lower values of the liquid volume flow rate at the pipeline outlet compared to the results of the dynamic simulation. The dynamics of the liquid removal from the pipeline with an increase of the gas flow rate is studied. It is shown that the surge liquid volume increases sharply at a rapid growth of the gas flow rate, which leads to restrictions on the increase in the well flow rate. Keywords: subsea pipeline; natural gas; multiphase fluid; liquid accumulation; slug flow.

Falling film co-current flow cyclone demister for separating high-boiling droplets: Gas-liquid flow pattern and performance

In many processes, the product gas stream contains liquid droplets that easily condense or solidify, which can deteriorate demister performance and even block equipment during gas–liquid separation. We proposed a falling film co-current flow cyclone demister (F2CFCD) to solve the above problems. The novel idea is that an additional stream of solvent fluid is added to the gas stream containing the droplets. After injecting the demister, the solvent fluid forms a film on the wall of F2CFCD. When the droplets are separated to the wall surface by centrifugal force, they are dissolved by the liquid film, thereby avoiding crust formation. In this work, the gas–liquid flow characteristics and the performance of F2CFCD are investigated numerically and experimentally. A hot-wire anemometer (HWA) is used to measure the gas velocity, and a conductivity method is used to measure the liquid film thickness. A coupled numerical model of the RSM-DPM and Eulerian wall film (EWF) model is applied to discuss the effect of the gas–liquid flow rate on the flow field in the demister. The liquid volume flow rates ranges from 0.5–10.5 m3/h, and the gas volume flow rates range from 640–894 m3/h. The gas flow pattern and the liquid film flow regimes are explored in the F2CFCD. A film thickness model is established to evaluate the average film thickness in the waterfall regime. Experimental observations illustrate that F2CFCD has a high separation efficiency for droplets under all conditions.

Theoretical and experimental investigation for developing a gas-liquid two-phase flow meter

Despite the intricacy, inline metering of two-phase flow has a significant impact in multitudinous applications including fusion reactors, oil, nuclear, and other cryogenic systems. Since measurement of individual flow rate is prominent in various systems, it warrants the establishment of a flow meter system that can monitor the mass flow rates of liquid. In this regard, an approach was taken towards the development of a two-phase flow meter system in the present study. The concept involves two-phase flow through narrow parallel rectangular channels resulting in laminar, stratified flow with a slope at the liquid-vapor interface. The height of the liquid column at specific channel locations is measured for determining the flow rate. However, the geometric configurations of the channels and fluid properties are pivotal in ensuring accurate measurement. Consequently, theoretical and experimental studies are performed to investigate the correspondence between flow rate and change in liquid height. Based on the governing equations, a theoretical model is established using MATLAB®. The model investigated the intricate influence of various flow and fluid properties in the estimation of the mass flow rate. The experimental investigation was done with various conditions under different liquid and vapor volume flow rates for validating the proposed supposition and the theoretical model. Both the theoretical and experimental analyses showed fair correspondence. The proposed system estimated the mass flow rate within a tolerance of ±10% and showed potential towards the development of the cryogenic two-phase flow meter.

Nanoporous polypropylene membrane contactors for CO2 and H2S capture using alkali absorbents

The paper reports a comprehensive review of the performance of nanoporous gas-liquid polypropylene membrane contactor with NaOH absorbents for removal of H2S and CO2 components from the gas streams. The experiments at different operation conditions, including variation of acid gas content in a feed stream, alkali concentration in absorbent, gas and liquid absorbent volume flow rates, absolute and gas-liquid differential pressures are discussed as a function of the absorbent saturation levels. In-liquid diffusion of components and gas/membrane contact times were determined as main governing factors limiting contactor efficiency. Mass transfer rates of acid gas removal on the membrane contactor over 3 × 10−3 mol/(m2 × s) for CO2 and 7.5 × 10−3 mol/(m2 × s) for H2S were attained. Ultimate processed gas quality with H2S content below 5 ppm and CO2 content below 0.01% was achieved at the contactor performance over 7 m3/(m2 × h) and initial acidic gas content of 2%, while achieving a membrane packing density in the contactor over 3000 m2/m3. The paper also provides an experimentally-proven theoretical model for calculating removal efficiency and residual acid gas partial pressures depending on the membrane parameters and operation conditions. It is shown, the mass transfer coefficient and removal efficiency differ significantly for H2S and CO2 due to the difference in dissolution mechanism involving kinetically limited deprotonation reaction of solvated water in case of CO2(aq) while engaging direct deprotonation of H2S. This allows to attain residual partial pressure of H2S in retentate stream equal to the equilibrium pressure above the absorbent solution, while CO2 residual pressure exceeds an equilibrium value few orders of magnitude. The effect has been successfully utilized for the selective removal of H2S from both CO2 and H2S-containing mixtures with H2S/CO2 selectivity exceeding 1500.

Formation and Elimination of Satellite Droplets during Monodisperse Droplet Generation by Using Piezoelectric Method.

One of the key questions in the generation of monodisperse droplets is how to eliminate satellite droplets. This paper investigates the formation and elimination of satellite droplets during the generation of monodisperse deionized water droplets based on a piezoelectric method. We estimated the effects of two crucial parameters—the pulse frequency for driving the piezoelectric transducer (PZT) tube and the volume flow rate of the pumping liquid—on the generation of monodisperse droplets of the expected size. It was found that by adjusting the pulse frequency to harmonize with the volume flow rate, the satellite droplets can be eliminated through their coalescence with the subsequent mother droplets. An increase in the tuning pulse frequency led to a decrease in the size of the monodisperse droplets generated. Among three optimum conditions (OCs) (OC1: 20 mL/h, 20 kHz; OC2: 30 mL/h, 30 kHz; and OC3: 40 mL/h, 40 kHz), the sizes of the generated monodisperse deionized water droplets followed a bimodal distribution in OC1 and OC2, whereas they followed a Gaussian distribution in OC3. The average diameters were 87.8 μm (OC1), 85.9 μm (OC2), and 84.8 μm (OC3), which were 8.46%, 6.14%, and 4.69% greater than the theoretical one (81.0 μm), respectively. This monodisperse droplet generation technology is a promising step in the production of monodisperse aerosols for engineering applications.

Investigation of Oil Droplet Breakup during Atomization of Emulsions: Comparison of Pressure Swirl and Twin-Fluid Atomizers

The goal of this study was to investigate oil droplet breakup in food emulsions during atomization with pressure swirl (PS), internal mixing (IM), and external mixing (EM) twin-fluid atomizers. By this, new knowledge is provided that facilitates the design of atomization processes, taking into account atomization performance as well as product characteristics (oil droplet size). Atomization experiments were performed in pilot plant scale at liquid volume flow rates of 21.8, 28.0, and 33.3 L/h. Corresponding liquid pressures in the range of 50–200 bar and air-to-liquid ratios in the range of 0.03–0.5 were applied. Two approaches were followed: oil droplet breakup was initially compared for conditions by which the same spray droplet sizes were achieved at constant liquid throughput. For all volume flow rates, the strongest oil droplet breakup was obtained with the PS nozzle, followed by the IM and the EM twin-fluid atomizer. In a second approach, the concept of energy density EV was used to characterize the sizes of resulting spray droplets and of the dispersed oil droplets in the spray. For all nozzles, Sauter mean diameters of spray and oil droplets showed a power-law dependency on EV. PS nozzles achieved the smallest spray droplet sizes and the strongest oil droplet breakup for a constant EV. In twin-fluid atomizers, the nozzle type (IM or EM) has a significant influence on the resulting oil droplet size, even when the resulting spray droplet size is independent of this nozzle type. Overall, it was shown that the proposed concept of EV allows formulating process functions that simplify the design of atomization processes regarding both spray and oil droplet sizes.

Experimental study on interfacial and wall friction factors under counter-current flow limitation in vertical pipes with sharp-edged lower ends

Experiments on air-water counter-current annular flows in circular vertical pipes of 20 and 40 mm in diameter were carried out to obtain databases of the interfacial and wall friction factors. The pipes were made of transparent acrylic resin to observe counter-current flow limitation (CCFL) in the pipe. The vertical pipe was connected to an upper and a lower tank. The liquid and gas phases were supplied to the upper and lower tanks, respectively. The liquid volume flow rate, the pressure gradient and the liquid volume fraction were measured to evaluate the friction factors. The flows in the pipe were observed using a high-speed video camera and the flow pattern under CCFL was identified using the time-strip visualization technique. The main conclusions obtained under the present experimental conditions are as follows: (1) the flows under CCFL condition can be classified into four regimes, i.e. the smooth film, the transition from smooth film to rough film regimes, the rough film with large amplitude disturbance waves forming at the lower pipe end, and the rough film with simultaneous onsets of disturbance waves inside the pipe, (2) the slope of the CCFL diagram depends on the flow regimes, (3) the flow structure strongly affects the friction factors, and therefore, available correlations of friction factors not accounting for their dependences on the flow regimes cannot give good evaluations, (4) the wall friction factor can be correlated in terms only of the liquid Reynolds number, (5) the interfacial friction factor in the rough film regimes can be well correlated in terms of the gas Wallis parameter (Froude number) since the interface structure strongly depends on the Wallis parameter, and (6) the CCFL model derived using the present empirical correlations of friction factors agrees well with the CCFL characteristics data.

Gas hold up in bubble column at high pressure and high temperature

Gas holdup of water/nitrogen, water-phenol/nitrogen and water-phenol/air systems was successfully measured by a method based on the use of a differential pressure sensor installed on a bubble column reactor, in a wide domain of temperature (from 100 to 300 °C) and pressure (from 10 to 30 MPa). These experimental conditions are little or no explored in literature. Results show a predominant influence of the superficial gas velocity, the evaporation of the liquid phase, the ratio of the gas volume flowrate on the liquid volume flowrate and the phenol concentration. Pressure and chemical reaction have little effect on gas holdup. The temperature has an effect in the case of phenol solutions. The different correlations and parameters influence determined in this work are very helpful for the design of gas liquid contactors (for instance bubble column) at high pressure and high temperature.

Primary breakup dynamics and spray characteristics of a rotary atomizer with radial-axial discharge channels

An experimental investigation of primary breakup dynamics and spray characteristics of a rotary atomizer with high aspect ratio radial-axial discharge channel is described. A high-resolution shadow imaging technique with pulsed backlight illumination was used for spray visualization. For the rotary atomizer with high aspect ratio discharge channel and radial-axial orientation, visualization showed the occurrence of Centripetal–Coriolis-induced stream-mode injection for all operating conditions. In this mode of injection, a crescent liquid film forms in the channel exit and issues from the orifice as a liquid column or a thin liquid sheet depending on atomizer operating conditions. It was found that the liquid Weber number value determines the state of the injected liquid stream (column or sheet) during the breakup process. The breakup process was studied with the variation of rotational speed and liquid volume flow rate. A morphological classification of the different modes of breakup is obtained from the flow visualizations. Four breakup modes have been observed for the present range of test parameters. These include Rayleigh, bag, stretched ligament, and shear breakup modes. These modes are separated by transitional regimes. The results suggest qualitative similarities between the primary breakup of the present rotary atomizer with a non-turbulent liquid jet and a fan like liquid sheet under a gas cross flow. The maximum liquid stream penetration height was measured for some operating conditions. It is concluded that this parameter is depend on the momentum flux ratio and liquid Weber number. To further evaluate features of the spray, the droplet size measurements have been conducted using the PDIA technique. The results indicate that there is a relatively strong correlation between the SMD values and liquid Weber number, while a properly non-dimensionalized droplet size is well correlated with the momentum flux ratio and Rossby number.

Effect of geometrical parameters on slug behaviour and two phase pressure drop in microchannel T-junctions

Geometric parameters of a microchannel such as cross-sectional area, shape and aspect ratio are important factors in determining the two phase flow characteristics. Two phase flow analyses were carried out experimentally for microchannel T-junction geometries at low values of capillary number. Three hydraulic diameters were used, namely 250, 400 and 550 μm, while the aspect ratio was varied between 0.1 to 1. Experiments were performed for the gas volume flow rate ranging from 2 to 30 ml/min while the liquid volume flow rate ranged between 0.1 to 10 ml/min. Slug length was estimated from the processing of high speed images of slug flow and pressure drop was simultaneously recorded. For constant mass flux in rectangular channels, an increase in the aspect ratio leads to an entrapment of continuous phase at the corner. This influences the transport characteristic of such channels. The effects of aspect ratio on slug length and pressure drop are reported. A simplified scaling model based on the geometric parameters of microchannels as well as gas and liquid flux is proposed which agrees reasonably well (within ±15%) with the present experimental data as well as data available in literature. A flow based pressure drop prediction model was developed which agrees well (within ±10%) with the experimentally measured two phase pressure drop. It is believed that a priori information on slug length and pressure drop in a given flow through a microchannel will help to design the flowing system better.

Experimental investigation of flow patterns and external performance of a centrifugal pump that transports gas-liquid two-phase mixtures

In order to reveal the mechanism of two-phase flow inside a centrifugal pump, visualization experiments were performed to investigate the gas-liquid two-phase flow patterns by using high-speed photography. Meanwhile, the external performance of the pump was measured under different conditions. The flow patterns in the suction pipe can be classified into plug flow and stratified flow distinguished by the critical inlet gas volume fraction (IGVF) of 6.2%. The critical IGVF of the pump is not obviously influenced by the rotational speed and initial liquid volume flow rate. The flow patterns in the impeller and volute can be classified into four categories with the increasing IGVF. The liquid volume flow rate has a small change in the condition of isolated bubbles flow, an obvious decrease in the condition of bubbly flow, a sharp decrease in the condition of gas pocket flow, and a gentle reduction in the condition of gas-liquid separation flow. Once the IGVF reaches the critical value, some bubbles in the volute begin to flow back into the impeller near the volute tongue. When the flow pattern transfers from gas pocket flow to gas-liquid separation flow, some bubbles in the discharge pipe flow back into the impeller. When the height of gas in the suction pipe reaches a critical value about 70 mm, bubbles sometimes flow into the volute and sometimes flow back into impeller, and the liquid volume flow rate is nearly to be zero. The differential pressure of the pump decreases with the increase of IGVF, and it decreases with the increase of initial liquid volume flow rate at the same IGVF.

A two-phase MMC–LES model for turbulent spray flames

A multiple mapping conditioning/large eddy simulation model (MMC–LES) is formulated for turbulent spray flames. Heat and mass transfer between the gaseous and liquid phases is modelled using a conserved scalar form of the Spalding transfer number approach along with an evaporative mixing model that is local in mixture fraction space. The model and the numerical implementation are tested in a non-reacting and two reacting experimental acetone spray cases. Model predictions are generally in good agreement with the velocity, liquid volume flow rate and mean temperature data and are shown to have a low sensitivity to the sparse stochastic particle resolution. The consistency of the heat and mass transfer coupling between the hybrid Eulerian–Lagrangian–Lagrangian schemes is demonstrated by comparison of mixture fraction fields solved on both the LES and the stochastic particles. A comprehensive appendix contains a derivation of the phase-weighted form of the MMC–LES governing equations along with a derivation and single-droplet test of the conserved scalar heat and mass transfer formulation.

Impact of inclination on single phase heat transfer in a partially filled rotating pipe

Heat transfer in a partially-filled, rotating inclined pipe with water flowing through it is experimentally investigated. The test section is a 1000 mm long stainless steel pipe with 32.8 mm inner diameter and 1.1 mm wall thickness. The outer wall is painted black to improve its emissivity. The outer wall temperature distribution is captured using a thermal camera. Uniform wall heat flux (1405–10784 W/m2), water volumetric flow rate (100–830 ml/min), rotation rate (10–300 RPM) and pipe inclination angle (3° and 6°) are varied to study their influence on the heat transfer coefficient. Local heat transfer coefficient along the length of the partially filled rotating test section is reported. While heat transfer coefficient increases with the increase in wall heat flux, liquid volume flow rate and rotation rate, it decreases with increase in inclination angle. A generalised correlation to predict the average Nusselt number is developed in terms of four dimensionless numbers, viz., the flow Reynolds number to capture the effect of the axial fluid flow, rotation Reynolds number to account for the effect of pipe rotation, flow Froude number to take care of the effect of pipe inclination and dimensionless heat flux to incorporate the effect of wall heat flux on the heat transfer coefficient.