Liquid Temperature Research Articles

Investigation of the influence of different liquid temperatures on the dynamics of long-pulse laser-induced cavitation bubbles

Long-Pulse Laser-induced cavitation bubbles have been identified to hold significant applications in various fields, such as industry and medicine. In this study, the dynamics of cavitation bubbles, induced by a 2.94 μm wavelength Er:YAG laser with an energy of 20 ±1 mJ and transmitted via sapphire fiber optics into distilled water at different temperatures, were investigated. The adiabatic expansion theory was utilized to predict the maximum length (Lmax) and the maximum width (Wmax) of the cavitation bubbles at different liquid temperatures. Excellent alignment was observed between the theoretical predictions and the experimental data. Using this theory, the local overheated liquid temperature was deduced to be ∼180 °C during the formation of cavitation bubbles. It was found that as the liquid temperature increased, the collapse position of the cavitation bubbles, relative to the normalized distance (γ) from the fiber end face, decreased. This study reveals the importance of considering the potential risk of damage to fiber optics from the shockwaves and microjet streams generated by cavitation bubbles in high-temperature conditions.

Accelerated modeling and design of a mixed refrigerant cryogenic process using a data-driven approach

Cryogenic processes with mixed refrigerants are prevalent in energy-intensive chemical industries, enhancing energy efficiency while reducing costs and unit size. However, the curse of dimensionality and process design constraints pose significant hurdles for effective screening and optimization. To tackle this, we developed a neural network model for natural gas liquefaction prediction. Trained on an extensive Aspen HYSYS database, our ML model accurately simulates LNG processes, with an impressive R2 test value of 99.63, operating almost ten million times faster than HYSYS. It effectively addresses vital process design constraints, including liquid slugging and temperature cross, crucial for optimization. By integrating the ML model with genetic and Nelder–Mead algorithms, we achieve an 8.9% reduction in total exergy, outperforming Aspen HYSYS within the same time frame. Our study underscores ML’s significance in modeling energy-intensive chemical processes, providing insights into the exergy profile and enabling feature importance analysis.

Effectiveness of Maxwell velocity and smoluchowski thermal slip constraints in presence of non-uniform heat source

Magnetohydrodynamic flow of nanomaterial by a stretched boundary is addressed. Entropy generation is examined. Variable fluid characteristics are considered. Buongiorno thermal enhancement model in presence of Darcy-Forchheimer expression is addressed. Nonlinear thermal radiation, non-uniform heat source and dissipation are considered in thermal expression. Slip conditions in chemically reactive flow are addressed. Here Maxwell slip velocity and Smoluchowski slip temperature are under consideration. Impact of Arrhenius activation energy is deliberated. Optimal homotopy analysis approach (OHAM) is utilized for construction of convergent solutions. Graphical description for liquid motion, entropy rate, concentration and temperature are examined. Higher magnetic variable has reverse effect on entropy rate and velocity. Higher temperature and entropy rate are seen for radiation parameter. Higher temperature dependent conductivity parameter has opposite effect on liquid motion and entropy rate. Liquid flow has same impact for both porosity and velocity slip parameters. Larger thermal slip variable lead to decrease thermal distribution while reverse impact holds for heat source. Concentration has opposite trend through both random and thermophoresis parameters. An enhancement in thermal distribution and entropy rate are seen through variable thermal conductivity. An intensification in entropy rate has been noticed through concentration dependent conductivity variable. The considered configuration has relevance for detecting cooling towers, polymer extrusion, spinning of filaments, cable coating and metallurgical processes.

Ground- and ship-based microwave radiometer measurements during EUREC4A

Abstract. During the EUREC4A field study, microwave radiometric measurements were performed at Barbados Cloud Observatory (BCO) and aboard RV Meteor and RV Maria S Merian in the downstream winter trades of the North Atlantic. We present retrieved integrated water vapor (IWV), liquid water path (LWP), and temperature and humidity profiles as a unified, quality-controlled, multi-site data set on a 3 s temporal resolution for a core period between 19 January and 14 February 2020 in which all instruments were operational. Multi-channel radiometric measurements were performed at BCO and aboard RV Meteor between 22 and 31 GHz (K-band) and from 51 to 58 GHz (V-band). Combined radar–radiometer measurements of a W-band Doppler radar with a single-channel radiometer instrument were conducted at 89 GHz aboard RV Meteor and RV Maria S Merian. We present a novel retrieval method to retrieve LWP from single-channel 89 GHz measurements, evaluate retrieved quantities with independent measurements, and analyze retrieval uncertainties by site and instrument intercomparison. Mean IWV conditions of 31.8 kg m−2 match independent radiosoundings at BCO with a root-mean-square difference of 1.1 kg m−2. Mean LWP conditions in confidently liquid cloudy, non-precipitating conditions ranged between 63.1 g m−2 at BCO and 46.8 g m−2 aboard RV Maria S Merian. Aboard the ships, 90 % of LWP was below 120 g m−2 with a 30 % uncertainty for LWP of 50 g m−2. Up to 20 % of confidently liquid cloudy profiles ranged below the LWP detection limit due to optically thin clouds. The data set comprises of processed raw data (Level 1), full quality-controlled post-processed instrument data (Level 2), a unified temporal resolution (Level 3), and a ready-to-use multi-site time series of IWV and LWP (Level 4), available to the public via AERIS (https://doi.org/10.25326/454##v2.0; Schnitt et al., 2023a). The data set complements the airborne LWP measurements conducted during EUREC4A and provides a unique benchmark tool for satellite evaluation and model–observation studies.

Uncertainty Propagation in a Simplified Integrated Thermal Management System

An integrated generic plate model that describes single-phase transport combining heat acquisition and rejection regimes is investigated. Transient processes and input uncertainty propagation impacting temperature variations in this simplified, dimensionless integrated thermal management system are discussed. The heat acquisition plate is surface-heated on one side, with the heat being conducted into a liquid. The heated liquid is assumed to be adiabatically advected to the heat rejection plate. Convection boundary conditions are considered for both plates. The range of mean values of dimensionless input parameters, such as the Biot and Prandtl numbers, is determined by the choice of a particular plate metal and flowing liquid, and their stochastic nature is described by the Gaussian distributions. Adiabatic solutions for the dimensionless temperature variations in the plates are obtained for different temperatures and Reynolds numbers. As is shown, even an assumed small standard deviation for the input parameters may result in a drastic increase in the stochastic spread in the temperature variation in the heat rejection plate. Unlike the temperature variation across the acquisition plate, the temperature variation profile for the heat rejection plate is sensitive to the temperature of the incoming liquid and heat input at the acquisition plate.

Thickening human milk: the effect of time, temperature, and thickener for infants with dysphagia.

Time, temperature, and thickening agents have a significant impact on the thickness level when added to expressed human milk. Certain foods such as fruit purees, squash, yogurt, and raw oatmeal may effectively thicken human milk, and the IDDSI flow test can assess if the mixture maintains a similar thickness level over time. These foods could be considered for older infants with dysphagia. When thickening human milk for infants with dysphagia, close physician and clinician monitoring is recommended given the potential positive and/or negative consequences on oral feeding and overall health. • Thin liquids can be challenging for infants with dysphagia to safely swallow Human milk is difficult to thicken. • Pureed fruits and pureed squash thicken human milk effectively at various temperatures and maintain thickness level over 20 minutes. • Pureed fruits and pureed squash thicken human milk effectively at various temperatures and maintain thickness level over 20 Raw oatmeal cereal either thins over time or thickens over time depending on the temperature of the base liquid.

Theoretical Study of Liquid Flow and Temperature Distribution in OF-Cooled Power Transformers

The objective of the paper is to analyse the effects of various geometrical and operating parameters on the liquid flow distribution in OF-cooled power transformers. Our investigation includes two cases: one with a simplified winding geometry and another that closely resembles the actual winding geometry. The analyses were carried out using computational fluid dynamics (CFD) and custom, internally developed thermo-hydraulic models. Our findings confirm that buoyancy forces rather than the pump drive the liquid flow within the windings of an OF-cooled power transformer. The results also show that the liquid flow distribution, which is influenced by the winding geometrical properties and liquid properties, has a significant impact on the hot-spot temperatures of the windings. The comparison between the results of the CFD simulations and the results of the simple model demonstrates a high level of agreement in calculating both the mass flow rates and temperatures.

Cross-sectional temperature field of a solar collector’s absorber in the case of annular pipe

In households, solar collectors are finding ever increasing use for hot water preparation. Although the design of solar collectors is relatively simple, the authors over many years concentrate attention on modelling the cross-sectional temperature field of the solar collector’s absorber [1-7]. In solving the cross-sectional temperature field for an annular pipe [1], the periodical cross-sectional domain is divided into three sub-domains where the first sub-domain is the plate between pipes, the second – a pipe’s wall, and the third – the liquid; as a result, the temperature field expressions have been obtained for all the three sub-domains. In works [2, 3] the temperature fields obtained were simplified. To define its variations in time, the temperature field was found by solving the Laplace equation under non-stationary time-dependent conditions [4]. The obtained results evidence that the non stationary conditions might not be taken into account in long- lasting sunny weather, while such non-stationarity changes considerably the temperature field when it is short-term (e.g. in cloudy weather). The temperature has also been found for a square-pipe absorber [7] as more technological in design. In the present work, the final temperature field model is proposed for the absorber of a round-pipe collector. As distinguished from [1], in this work the temperature of liquid is assumed to be constant over the entire pipe cross-section. Such an assumption significantly simplifies the calculation while not changing the physical essence.

Design of anti-temperature interference liquid level sensor based on π-phase-shifted LPFG near phase-matched turning points

A new, to the best of our knowledge, type of liquid level sensor with π-phase-shifted long-period fiber grating operating near the phase-matched turning point is proposed. The sensor introduces a π-phase shift at the center of the grating, which can generate three attenuation peaks due to the mode interference effect in the transmission spectrum of the sensor operating near the phase-matched turning points. According to the different liquid level and temperature sensing characteristics of three attenuation peaks, simultaneous detection of liquid level and temperature can be realized through wavelength modulation and intensity modulation detection. In this paper, the structural parameters of this liquid level sensor, such as grating period and grating length, are designed optimally based on the fiber grating coupled mode theory, and the wavelength spacing of the attenuation peaks on both sides and the intensity of the center attenuation peak are analyzed in relation to the liquid level and temperature. The simulation results show that the liquid level sensitivity is 5.58 nm/mm and −1.316dB/mm for wavelength modulation and intensity modulation, respectively, for the liquid level variation range of 0 to 18 mm; and the temperature sensitivity of wavelength modulation and intensity modulation is −0.139nm/∘C and 0.171 dB/°C, respectively, over the temperature variation range of 20°C to 80°C. Therefore the simultaneous detection of liquid level and temperature can be realized by establishing a measurement inversion matrix. Compared with other liquid level sensors, this sensor is expected to be widely used in the field of liquid level sensing due to its simple structure, high liquid level sensitivity, large liquid level measurement range, and narrow monitoring peak bandwidth.

Melting, Solidification, and Viscosity Properties of Multicomponent Fe-Cu-Nb-Mo-Si-B Alloys with Low Aluminum Addition.

Melting, solidification, and viscosity properties of multicomponent Fe-Cu-Nb-Mo-Si-B alloys with low aluminum addition (up to 0.42 at.% Al) were studied using an oscillating cup viscometer. It is shown that melting and solidification are divided into two stages with a knee point at 1461 K. The temperature dependences of the liquid fraction between the liquidus and solidus temperatures during melting and solidification are calculated. It has been proven that aluminum accelerates the processes of melting and solidification and leads to an increase in liquidus and solidus temperatures. In the liquid state at temperatures above 1700 K in an alloy with a low aluminum content, the activation energy of viscous flow increases. This growth was associated with the liquid-liquid structure transition, caused by the formation of large clusters based on the metastable Fe23B6 phase. Aluminum atoms attract iron and boron atoms and contribute to the formation of clusters based on the Fe2AlB2 phase and metastable phases of a higher order.

SLAG—software for reconstruction of historical smelting processes based on slag properties

AbstractThe publication presents the functions of the SLAG software created to recreate historical metallurgical processes. SLAG allows for determining the smelting temperature, the viscosity of the metallurgical melt, and the oxygen and sulfur fugacities during smelting. With software, both liquidus temperature and melt viscosity can be calculated using different models, covering the range of chemical compositions of historical slags as wide as possible. Based on thermodynamic calculations, SLAG allows the performance of O2 and S2 fugacity calculations in the temperature range of 1000–2000 K (727–1727°C). The range of applicability of other properties (viscosity and liquidus temperature) depends only on the limitations of individual models. Using SLAG, it is also possible to create predominance area diagrams (PADs) and diagrams that consider the viscosity's dependence on temperature for slag of a given chemical composition. Based on glass transition temperature (Tg) and melt fragility, it is also possible to reconstruct the conditions that prevailed during the various stages of historical glass manufacturing processes.

Metachronal wave analysis for magnetized Williamson fluid through a ciliated curved channel

Cilia play an important role in many psychological processes such as locomotion, alimentation, circulation, respiration, and reproduction. Therefore, the present investigation is modeled to study the impact of velocity slip on the cilia motion of electrically conducting Williamson fluid in a curved channel. The walls of the channel are carpeted with cilia such that their coordinated beatings produce a metachronal wave. Moreover, the viscous dissipation effect is also observed through the heat transfer mechanism. The governing system of coupled partial differential equations with highly nonlinear terms is simplified using the long wavelength and low Reynolds number approximations. The numerical solutions of simplified normalized equations are obtained using the finite difference method with an incorporating relaxation algorithm. The outcomes regarding the influences of several physical parameters on the temperature, velocity, pumping characteristics, and stream function are examined through graphs. Furthermore, the skin friction and Nusselt number at the channel walls are determined for a variety of critical parameter assessments. It is concluded that the fluid velocity is diminished at the lower wall of the channel and enhanced at the upper wall of the channel by enhancing the values of the Weissenberg number. The Brickman number shows a stronger viscous dissipation effect, leading to an increase in the liquid temperature.

Supercooled liquid water clouds observed over Dome C, Antarctica: temperature sensitivity and cloud radiative forcing

Abstract. Clouds affect the Earth climate with an impact that depends on the cloud nature (solid and/or liquid water). Although the Antarctic climate is changing rapidly, cloud observations are sparse over Antarctica due to few ground stations and satellite observations. The Concordia station is located on the eastern Antarctic Plateau (75∘ S, 123∘ E; 3233 m above mean sea level), one of the driest and coldest places on Earth. We used observations of clouds, temperature, liquid water, and surface irradiance performed at Concordia during four austral summers (December 2018–2021) to analyse the link between liquid water and temperature and its impact on surface irradiance in the presence of supercooled liquid water (liquid water for temperature less than 0 ∘C) clouds (SLWCs). Our analysis shows that, within SLWCs, temperature logarithmically increases from −36.0 to −16.0 ∘C when liquid water path increases from 1.0 to 14.0 g m−2. The SLWC radiative forcing is positive and logarithmically increases from 0.0 to 70.0 W m−2 when liquid water path increases from 1.2 to 3.5 g m−2. This is mainly due to the downward longwave component that logarithmically increases from 0 to 90 W m−2 when liquid water path increases from 1.0 to 3.5 g m−2. The attenuation of shortwave incoming irradiance (that can reach more than 100 W m−2) is almost compensated for by the upward shortwave irradiance because of high values of surface albedo. Based on our study, we can extrapolate that, over the Antarctic continent, SLWCs have a maximum radiative forcing that is rather weak over the eastern Antarctic Plateau (0 to 7 W m−2) but 3 to 5 times larger over West Antarctica (0 to 40 W m−2), maximizing in summer and over the Antarctic Peninsula.

EN Optimization strategy for system management of cold thermal energy storage (CTES) in conditions of dynamic changes in energy carrier value

In world of contemporary challenges involving the continual increase in demand for energy resources and corresponding environmental pollution, the necessity has arisen to develop and implement advanced technologies to reduce energy consumption. This calls for enhancing energy utilization efficiency and optimizing energy generation systems, taking into account the utilization of alternative and renewable energy sources. Specifically, thermal energy storage becomes crucial as an effective economic option. Thermal energy storage systems enable meeting heating or cooling needs during optimal periods when it is more energy-efficient. Traditional management methods rarely prove optimal due to fluctuating electricity tariffs, cooling loads, and ambient temperature. This leads to suboptimal achievement of maximum savings in the utilization of thermal energy storage systems. In this work, the advantages of Cold Thermal Energy Storage (CTES) systems based on Ice Thermal Energy Storage (ITES) were analysed alongside existing management strategies implemented in most enterprises and buildings utilizing ITES. A simplified engineering methodology for analysing the thermodynamic efficiency of CTES was proposed. It was determined that cold losses during exergy analysis during storage are caused by both losses through surfaces and internal exergy losses (i.e., exergy consumption due to irreversibility within the reservoir). For modern systems, exergy losses encompass both external and internal components. As an example, if the heat transfer at the external surface temperature of the storage reservoir equals the ambient temperature, external exergy losses would be zero, while total exergy losses would be entirely due to internal consumption. Conversely, if heat transfer occurs at the liquid's temperature for storage, a greater portion of exergy losses will be due to external losses. In all cases, the cumulative exergy losses, comprising internal and external exergy losses, remain constant. The implementation of CTES allows for shifting the use of electrical energy from peak to off-peak hours. During off-peak hours, electrical energy is used to charge the storage to fulfil (fully or partially) the peak demand for refrigeration equipment. Ice-based ITES has the potential to reduce maximum energy consumption, peak demand, and most importantly, the average cost of energy consumed

Adsorption Performance and Mechanism of Fe(II) Adsorption in Abandoned Mine Water of Nonstick Coal

Aiming at the problem of the low reuse rate of mine water due to the high content of heavy metals in mine water, in this research, the microcharacterization means of EDX, XRD, BET, SEM, and FT-IR were used to characterize the nonstick coal in a mine in western China. The effects of solid–liquid ratio, solution pH, solution temperature, adsorption time, and initial concentration of the solution on the adsorption of Fe(II) by the nonstick coal were analyzed. The adsorption performance of nonstick coal on adsorbed Fe(II) was analyzed under different influencing factors. The results showed that the adsorption capacity and unit removal rate of the coal samples gradually decreased with the increase in the solid–liquid ratio; the adsorption amount increased with the increase in pH in an “S” shape, and the adsorption effect was better in the range of pH = 5~7; and the adsorption amount increased linearly with the temperature. The quasi-secondary kinetic model and Langmuir model could fit the adsorption kinetic curve and isothermal adsorption curve better, which indicated that the adsorption of Fe(II) by the nonstick coal was dominated by the chemical adsorption of the monomolecular layer. The quantitative analysis of the FT-IR results showed that the adsorption of Fe(II) was mainly by complexation with -OH detached from the coal samples to produce precipitation.

An intrinsic connection between the liquid-liquid transition and fragile-to-strong transition in soft magnetic Fe-based metallic glasses: Comparisons with other metallic glasses

There are two significant abnormal transitions observed in metallic glass forming liquids (MGFLs), i.e., liquid-liquid transition (LLT) above liquidus temperature and fragile-to-strong (F-S) transition in supercooled region. In this study, we focus on the correlation between LLT and F-S transition in Fe-based soft magnetic metallic glasses (MGs) for the first time. We find that the more distinct the LLT is, the weaker is the F-S transition, and the smaller is the glass forming ability (GFA). By employing molecular dynamics simulation, we identify that this relationship is due to the inherent correlated evolution trends of crystal-like clusters between the LLT and the F-S transition regions. Moreover, we analyze a general rule regarding the LLT and F-S transition in MGs, along with their composition-dependent peculiarities. This work sheds light on the process of liquid-solid inheritance of different MGs, and deepens the understanding of the liquid dynamics of MGs and their following GFA.

Heat transfer near a growing bubble during nucleate boiling using dual-tracer laser-induced fluorescence thermometry

Boiling heat transfer associated with bubble growth is perhaps one of the most efficient cooling methodologies due to its large latent heat during phase change. Despite the significant advancements, numerous questions remain regarding the fundamentals of bubble growth mechanisms, which is a major source of enhanced heat dissipation. This work aims to accurately measure three-dimensional (3D), space and time-resolved, local liquid temperature distributions surrounding a growing bubble to quantify the heat transfer in the superheated liquid layer during bubble growth. The dual tracer laser-induced fluorescence thermometry technique combined with high-speed imaging captures transient 2D temperature distributions, that will render 3D temperature distributions by combining multiple 2D layers, within a 0.3 °C accuracy at a 30 μm resolution. Two fluorescent dyes, fluorescein and sulforhodamine B, were used to measure transient temperatures, by account of their temperature-sensitive emissions. The results show that the temperature close to the heated surface and bubble interface exhibits an acute transient behavior at the time of bubble departure. The growing bubble works as a pump to remove heat from the surface with a peak temperature difference of up to 10 °C during its growth and departure. The experimental results were compared with previously reported studies to validate the accuracy of the technique. It was found that the heat transfer coefficient close to the bubble interface and heater is approximately 1.3 times higher than the heat transfer coefficient in the bulk liquid.

Effect of different parameters utilized for image guided endodontic root canal preparation on temperature changes: an in vitro study

BackgroundNavigated endodontics is a cutting-edge technology becoming increasingly more accessible for dental practitioners. Therefore, it is necessary to clarify the ideal technical parameters of this procedure to prevent collateral damage of the surrounding tissues. There is a limited number of studies available in published scientific literature referencing the possible collateral thermal damage due to high-speed rotary instruments used in guided endodontic drilling. The aim of our study was to investigate the different drilling parameters and their effect upon the temperature elevations measured on the outer surface of teeth during guided endodontic drilling.MethodsIn our in vitro study, 72 teeth with presumably narrow root canals were prepared using a guided endodontic approach through a 3D-printed guide. Teeth were randomly allocated into six different test groups consisting of 12 teeth each, of which, four parameters affecting temperature change were investigated: (a) access cavity preparation prior to endodontic drilling, (b) drill speed, (c) cooling, and (d) cooling fluid temperature. Temperature changes were recorded using a contact thermocouple electrode connected to a digital thermometer.ResultsThe highest temperature elevations (14.62 °C ± 0.60 at 800 rpm and 13.76 °C ± 1.24 at 1000 rpm) were recorded in the groups in which drilling was performed without prior access cavity preparation nor without a significant difference between the different drill speeds (p = 0.243). Access cavity preparation significantly decreased temperature elevations (p < 0.01) while drilling at 800 rpm (8.90 °C ± 0.50) produced significantly less heating of the root surface (p < 0.05) than drilling at 1000 rpm (10.09 °C ± 1.32). Cooling significantly decreased (p < 0.01) temperature elevations at a drill speed of 1000 rpm, and cooling liquid temperatures of 4–6 °C proved significantly (p < 0.01) more beneficial in decreasing temperature elevations (1.60 °C ± 1.17) than when compared with room temperature (21 °C) liquids (4.01 °C ± 0.22).ConclusionsBased on the results of our study, guided endodontic drilling at drill speeds not exceeding 1000 rpm following access cavity preparation, with constant cooling using a fluid cooler than room temperature, provides the best results in avoiding collateral thermal damage during navigated endodontic drilling of root canals.

In-situ surface-enhanced Raman scattering on imidazole-based ionic liquids at variable temperatures

Ionic liquids (ILs) are unique solvents with a broad liquid temperature range. However, little has so far been done to investigate the ionic structures of ILs as a function of temperature. This can be performed by surface-enhanced Raman scattering (SERS) technique to effectively investigate the ionic structure and interface reaction of ILs at different temperature. Herein, in-situ SERS spectra of 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and 1-carboxyethyl-3-methylimidazolium chloride ([HO2CEtMIm]Cl) ILs adsorbed on silver substrates at variable temperatures were recorded to study the adsorption behaviors and enhancement mechanisms. The results suggested interaction between [EMIm]Cl and silver substrate through N-atoms with the imidazole ring standing on the substrate. The enhancement mechanism of silver substrates toward [EMIm]Cl originated from the combination of electromagnetic enhancement (EM) and chemical enhancement (CM). At temperatures of 25–200 °C, no significant changes in the adsorption behavior and ionic structure of [EMIm]Cl on the silver substrate surface were observed. However, a further temperature rise resulted in changes in SERS spectral intensity of [EMIm]Cl owing to the aggregation of silver particles, as well as the increment in the amount of adsorbed molecules. Besides, [HO2CEtMIm]Cl interacted with the silver substrate through the carboxyl group, resulting in a molecular configuration that greatly influenced the adsorption behavior of [HO2CEtMIm]Cl. Compared to [EMIm]Cl, the imidazole ring of [HO2CEtMIm]Cl was located farther away from the substrate surface, leading to weaker SERS enhancement. Finally, the temperature variation did not affect the adsorption behavior and ionic structure of [HO2CEtMIm]Cl on the substrate surface. Overall, these results look promising for future studies of ionic structure and interface reaction of various ILs for advanced synthesis processes.

Characteristics study of non-equilibrium flash for two-phase expansion based on equivalent expansion experiments

The two-phase expansion inside the expander could be divided into the non-equilibrium flash of superheated liquid and the expansion of the vapor. A higher flash rate would permit higher recovered expansion work. However, it is almost impossible to measure the flash rate inside the expansion chamber. In this paper, an equivalent expansion method s was proposed to study the non-equilibrium flash process for the two-phase expansion. The flash was controlled inside a constant volume flash chamber, which was connected to a vacuum tank to introduce and adjust the flashed vapor rate out of the flash chamber. The flash process inside the chamber was controlled under the working conditions similar to that inside the two-phase expander. By applying the equivalent expansion method, the flash rate could be measured easily. The experiments were carried out with an initial liquid height inside the chamber from 110 to 175 mm, and an initial liquid temperature from 110 to 130 °C with water as the working fluid. The instant flash rate and the PV diagram of the equivalent two-phase expansion were studied. Results showed that the instant flash rate increased and decreased sharply at first, and then the flash became gentle. Thus, the non-equilibrium flash of the two-phase expansion was divided into two stages of the rapid expansion process and the gradual expansion process. It was found that most of the flashed mass was generated during the rapid expansion process. Finally, a non-equilibrium flash model was proposed to simulate the flash process during the two-phase expansion process with the accuracy of ±3.7% predicting the pressure profile and the accuracy of ±2.7% predicting the expansion work.