Evaporative Heat Research Articles

Experimental study of fuel distribution and combustion characteristics under subatmospheric pressure in an afterburner

The fuel distribution and ignition characteristics of an afterburner with typical components under subatmospheric inlet conditions are important references for improving the performance of the afterburner at high flight altitudes. In this work, lean ignition limits, outlet temperature distributions, fuel droplet size distributions and flame propagation processes in the afterburner were obtained experimentally. The results show that with increasing fuel injection angle, the fuel atomization characteristics improve, but the flame intensity fluctuation increases, and the ignition performance deteriorates; thus, a proper ratio of liquid-phase fuel to vapor-phase fuel is one of the key elements for successful ignition. On the one hand, the increased stabilizer blockage ratio results in a localized flow velocity increase near the trailing edge of the stabilizer, which effectively promotes fuel atomization in the shear layer, resulting in a fuel droplet size reduction of 25–30 μm. On the other hand, the extent of the recirculation zone increases, and a large low-pressure and low-turbulence recirculation zone is not conducive to fuel atomization in the flow direction. During the ignition process in an afterburner with all the typical components, the flame kernel first propagates along the flow direction for a certain distance and then propagates and anchors toward the shear layer. At subatmospheric pressures, the decrease in the intensity of the combustion reaction causes a reduction in the heat released by combustion, and the fuel droplet size increases by 10–25 μm, which requires more heat for evaporation. Therefore, the flame propagates an increased distance along the flow as the pressure decreases. Furthermore, the difficulty of ignition increases, and the ignition equivalence ratio increases by 0.1–0.15.

Effect of ethanol addition on enhancing the cooling performance improvement of spray system

The widespread application of spray technology has significantly improved outdoor environmental thermal comfort. However, the spray system is unable to fulfill special comfort requirements. Utilizing mechanical ventilation and control systems effectively enhances the cooling performance of spray systems; however, those approaches are associated with elevated costs and maintenance complexities. The combination of ethanol and water has been demonstrated to produce a lower surface tension and a higher latent heat of evaporation, a property that contributes to the heat transfer efficiency and evaporation rate of the droplets. Considering the convenience and cost-effectiveness of adding ethanol as an additive, it emerges as the optimal choice. To evaluate the effectiveness of ethanol on the evaporative cooling performance of the spray system, a comparative study was conducted, comparing the cooling performances of different concentrations of ethanol with a spray system without ethanol addition. Five operating conditions were designed, including a no-spray case, a non-additive case, a 0.5% ethanol concentration case, a 1.0% ethanol concentration case, and a 1.5% ethanol concentration case. The results demonstrated that adding ethanol effectively enhanced the cooling performance of the spray system. At 1.7m above ground level (0.4m away from the nozzle), compared to the non-additive case without ethanol, the 0.5% ethanol concentration case, 1.0% ethanol concentration case, and 1.5% ethanol concentration case further reduced the temperature by 0.95°C, 1.64°C, and 2.27°C. Moreover, the relative humidity grew by 3.57%, 9.25%, and 13.5%, respectively. Adding ethanol significantly enhanced the evaporative cooling effect of the spray system, with the optimal concentration observed at 1.5%. The results demonstrate that enhancing the evaporative cooling efficacy of a spray system by introducing ethanol into the spray medium represents a viable strategy and improve urban thermal environment in summer. Furthermore, this study aims to examine the impact of droplet evaporation on relative humidity, establishing a foundation for future enhancements aimed at addressing the issue of over-humidification in spray systems.

Use of non-thermal treatment methods to ensure the quality and safety of fish and other hydrobionts. Overview of the subject field

Products of aquatic origin are among the most perishable products. Heat processing, including sterilization, drying and evaporation, can lead to undesirable changes in food products, such as a decrease in their nutritional value or deterioration in organoleptic characteristics. The purpose of the paper is to review the results of scientific research on non-thermal methods of processing fish and other aquatic organisms to inhibit bacteria, ensure microbiological safety and maintain quality. The groups of primary spoilage bacteria vary among fish, crustaceans and molluscs depending on storage conditions and duration. Non-thermal processing methods such as ultra-high pressure, irradiation, pulsed electric field and low-temperature plasma have shown significant results in inhibiting microbial growth and increasing the shelf life of aquatic products. However, uncertain processing parameters and characteristics of the technology itself can lead to adverse effects such as lipid oxidation and protein degradation during sterilization. Non-thermal processing can be used in combination with antioxidant composite coatings (membranes) to delay the oxidation of lipids and proteins and improve the physical, chemical and sensory properties of fish products. It is possible to combine several methods of non-thermal treatment, which will make it possible to compensate for the shortcomings of one technology by the action of another method of non-thermal exposure. Further scientific research should be aimed at establishing optimal processing modes, the possibility of combining non-thermal methods with other technologies, such as modified atmosphere packaging in order to determine the mechanisms of spoilage and improve the quality of storage of products of aquatic origin, as well as further industrial implementation of modern processing methods. BELROSAKAVA

Innovative temperature-responsive membrane with an elastic interface for biofouling mitigation in industrial circulating cooling water treatment

To address the issues of scaling caused by heat and water evaporation in regard to circulating cooling water (CCW), TFC membrane filtration systems have been increasingly considered for terminal treatment processes because of their excellent separation performance. However, membrane biofouling phenomenon significantly hinders the widespread utilization of TFC membranes. In this study, to harness the thermal phenomenon of CCW and establish a stable and durable multifunctional antibiofouling layer, temperature-responsive Pnipam and the spectral antibacterial agent Ag were organically incorporated into commercially available TFC membranes. Biological experimental findings demonstrated that above the lower critical solution temperature (LCST), the contraction of Pnipam molecular chains facilitated the inactivation of bacteria by the antibacterial agent, resulting in an impressive sterilization efficiency of up to 99 %. XDLVO analysis revealed that below the LCST, the establishment of a hydration layer on the functional interface resulted in the creation of elevated energy barriers, effectively impeding bacterial adhesion to the membrane surface. Consequently, a high bacterial release rate of 98.4 % was achieved on the low-temperature surface. The alterations in the functional membrane surface conformation induced by temperature variations further amplified the separation between the pollutants and the membrane, creating an enhanced "elastic interface." This efficient and straightforward cleaning procedure mitigated the formation of irreversible fouling without compromising the integrity of the membrane surface. This study presents a deliberately engineered thermoresponsive antibiofouling membrane interface to address the issue of membrane fouling in membrane-based CCW treatment systems while shedding new light on the mechanisms of "inactivation" and "defense."

Effect of charcoal balls on distillation productivity in hemispherical solar stills: Experimental investigation and performance analysis

This study investigates the enhanced performance of hemispherical solar stills by integrating charcoal balls. The method showcases improved efficiency by augmenting heat transfer mechanisms and enhancing solar radiation absorption. Reducing the surface tension of basin water is a solution to increase its heating, enhancing the softwater yield of solar stills. The novelty of the research lies in the innovative integration of charcoal balls to improve the performance of hemispherical solar stills. This method presents a unique approach to enhancing heat transfer and evaporation dynamics, potentially revolutionizing the efficiency of solar desalination systems. Therefore, the impact of charcoal balls at a diameter of 1 cm on the performance of distillation productivity was studied. A hemispherical solar still containing charcoal balls (HSS-CB) was compared with a simple hemispherical solar still (SHSS) in the same conditions. Experiments were conducted at El-Oued-Algeria in June 2024. The method employed in this research offers distinct advantages, primarily in its ability to enhance solar still efficiency by incorporating charcoal balls. These advantages stem from the increased surface area for heat transfer, improved solar radiation absorption, and potential enhancement of evaporation and condensation processes. Cumulative return results for SHSS and HSS-CB are 4.80 and 6.20 L/m2/day, respectively. The rate of improvement in the cumulative return was 29.16 % for SHSS using the quantity of coal powder. It is recommended that charcoal balls be used to boost solar stills productivity.

Ablation and molten layer flow simulation for plate model of SiO2f/SiO2 composite material using particle method

In this paper, the moving particle semi-implicit method (MPS) is extended from calculating free mobility to simulating the extremely viscous and temperature-dependent molten layer flow of SiO2f/SiO2 composite material under aerodynamic heating conditions, which includes strong heating and shear of incoming flow. A method for applying heat flux and airflow shear, based on the conceptual particle approach, has been established. Heat transfer, melting, solidification, and evaporation behaviors are considered, with temperature-dependent viscosity variations also accounted for. The ablative regression of the plate model is verified using experimental results of the SiO2f/SiO2 composite material, and results from convergence analysis demonstrate the accuracy of the space step size selection. Surface morphology analysis through three-dimensional computation indicates that the extended particle method also accurately describes the surface morphology of SiO2f/SiO2 composite material under aerodynamic heating conditions. Thus, the extended particle method accurately simulates both the ablation process and the surface morphology of the SiO2f/SiO2 composite material. The influences of acceleration and surface tension are discussed. Ablative recession, when subject to acceleration, is smaller than that observed in its absence. When exposed to surface tension, the liquid layer tends to form a spherical shape, and the particles behave as a cohesive unit, resulting in smaller ablative recession than in the absence of surface tension.

Coupled Wall Boiling and Population Balance Model for High Void Fraction Flows Under Sub-Cooled Nucleate Boiling Regime: Model Development and Validation

Abstract The subcooled flow boiling of water in a vertical annulus channel is studied numerically at low-pressure conditions. The two-fluid model is developed with flow-regime dependent interfacial transfers for mass, momentum, and energy using the algebraic interfacial area density (AIAD) framework. A discrete population balance model is used to mechanistically determine the vapor bubble diameter in the flow channel by considering the bubble aggregation and breakup effects. Energy balance at the heated wall for the subcooled nucleate boiling is handled using a suitable wall boiling model. A coupling is achieved between the discrete population balance and the wall boiling model for the nucleation and the growth rate of the vapor bubbles along the heated wall. The developed model simulates the reference experimental cases of flow boiling in a vertical channel for various flow and thermal conditions. At low wall heat flux, the wall boiling generates vapor bubbles near the heated wall and within the bubbly flow regime. With an increase in the wall heat flux, the aggregation and evaporation cause the formation of larger bubbles, which progress toward the flow channel core region, a phase that is representative of the transitional flow regime. The model's capability to predict such flow regime transition is validated with the experimental results. The bubble aggregation is found to be dominant compared to the breakup, and thus, proper choice of the aggregation factor is important for the accurate prediction of vapor parameters for the subcooled flow boiling at low-pressure conditions.

Construction of Cyclodextrin-Based Covalent Organic Frameworks for Efficient Encapsulation of Menthol.

The application of flavoring ingredients like menthol in the food industry is hindered by their high volatility and poor thermal stability, which lead to significant losses during processing and storage. Encapsulation of flavors into porous materials to obtain inclusion complexes (ICs) has proved to be an efficient strategy. In the present study, we synthesized a series of relatively food-safe three-dimensional anionic cyclodextrin-based covalent organic frameworks (CD-COFs) with spiroborate linkages using a facile microwave-assisted method. The high surface area and newly formed cavitied of COFs significantly enhanced the encapsulation efficiency of menthol compared to native CD materials. Our findings revealed that γ-CD-COF-Li, with Li+ as the counterion, achieved superior encapsulation efficiency of 25.9%, outperforming γ-CD-COF-Na, γ-CD-COF-K and α-CD-COF-Li under the same conditions. Thermal stability measurements show that the menthol/γ-CD-COF-Li-ICs effectively stabilize menthol against heat evaporation at elevated temperatures due to the strengthened interaction between menthol and γ-CD-COF-Li. The promising results of this research suggest that rapid advancements in COF technology will provide new opportunities for enhancing the stability of flavoring ingredients in the food industry.

Experimental research on chemisorption energy storage performance for industrial waste heat recovery and conversion

This study investigates a solid chemisorption energy storage system utilizing a multi-component chloride salt composite adsorbent with a mass ratio of NH4Cl, CaCl2, MnCl2, and expanded natural graphite treated with sulfuric acid (ENG-TSA). The system features a shell-and-tube heat exchanger and analyzes refrigeration and heat storage performance under varying industrial low-temperature waste heat (60–110 °C) conditions, with condensation and evaporation temperatures of 0–25 °C and discharging temperatures of 40–60 °C. The results indicate that the multi-salt composite adsorbent reduces hysteresis between adsorption and desorption stages. The highest coefficient of performance (COP) and specific cooling power (SCP) were 0.461 and 328 W/kg, respectively, at an evaporation temperature of 25 °C and a charging temperature of 110 °C. Excessively long cycle times negatively affect system efficiency, with optimal performance achieved at a 40-min cycle. The findings highlight the system's effectiveness for industrial low-grade waste heat recovery, providing a solid foundation for future reactor design and material selection.

An experimental investigation on frosting characteristics and performance of microchannel evaporators with varied aspect ratios

Microchannel evaporators are susceptible to frosting, which can significantly impair heat transfer performance. To provide a basis for microchannel evaporators' effective design and broad application, frosting experiments were conducted in this study. Leveraging infrared thermal imaging and digital image processing technology, the impact of different aspect ratios on refrigerant distribution was quantitatively measured, and the microchannel evaporators' frosting behavior and performance under frosting conditions were analyzed. The results showed that a higher aspect ratio for Evaporator C led to reduced uniformity in the refrigerant distribution, resulting in an increased frost height, a larger frosting coverage area, and greater frost accumulation. Consequently, as frost accumulated, Evaporator C exhibited the most discernible reductions in the heat transfer rate, evaporation pressure, and refrigerant pressure loss, which were 61.07 %, 31.7 %, and 52.83 %, respectively. Therefore, microchannel evaporators with small aspect ratios are recommended where practical field installation conditions permit. And the results are anticipated to provide useful guidance for selecting microchannel evaporators with the optimal aspect ratio, tailored to operate efficiently under frosting conditions.

Productivity, energy, and exergy analyses of a water desalination system-based vortex tubes with different configurations: An experimental implementation

The present implementation explores the use of vortex tubes (VTs) as an alternative thermal technology for water desalination systems (WDSs). VTs are utilized to provide hot air for evaporating salt water in the evaporator, while simultaneously supplying cold air to condense the water vapor in the condenser. The study investigates the influence of a number of operating parameters, including inlet water temperature (Ti,w), cold mass ratio (CR), and vacuum pressure (pvac) on the performance of WDS-based VTs through experimental analysis. Different configurations of VTs are tested for WDS applications, including WDS-based single vortex tube (VT), WDS-based two series vortex tubes (2SVTs), and WDS-based two parallel vortex tubes (2PVTs). Performance metrics such as the evaporation heat (QEvap), desalinated water production (DWP), gain output ratio (GOR), and exergy performance are evaluated for each configuration. Results show that the WDS-based 2SVTs exhibits the highest QEvap; while the WDS-based 2PVTs demonstrates the lowest value. Correlations are proposed to predict DWP for different configurations of WDS based on pvac, Ti,w, and CR with a maximum deviation of ±12.2 %. Furthermore, the WDS-based 2SVTs achieves the best GOR of 2.5 at an inlet water temperature of 80 °C, representing a significant improvement compared to the WDS-based VT and 2PVTs. The exergy efficiency (ηex) increases with higher CR, and the WDS-based 2SVTs ensures the best exergy performance, and its maximum overall ηex equals 78.2 %.

TiO2/Se heterojunction photovoltaic device made from Se/Te/Se stacked precursor

This paper presents an innovative approach for forming crystallized selenium (c-Se) using a Se/Te/Se stacked precursor. The aim is to enhance the adhesion between the TiO2 and Se layers to improve the power conversion efficiency of TiO2/Se heterojunction photovoltaic devices. Our previous study revealed that the accumulation of Te near the TiO2/Se interface resulted in insufficient shunt resistance, leading to increased dark leakage current. This issue arises because Te possesses a high carrier density (∼1018 cm−3) and narrow bandgap energy (0.26 eV). However, a Te additive layer remains necessary to passivate the unbonded TiO2/Se interface and to maximize the adhesion between the absorber and the substrate. Previous research on Se-based photovoltaic devices demonstrated that an extremely thin (∼0.5 nm) and homogeneous Te adhesion layer could be formed beneath the Se photo-absorbing layer and subsequently crystallized through air-annealing post-deposition. However, achieving precise and homogeneous sub-nanometer Te films using a compact resistance heating evaporation system in a laboratory setting proved challenging so far. To address these limitations, we propose a novel technique for forming the Se absorber layer by post-annealing a stacked 1st-Se/Te/2nd-Se precursor on a TiO2 window layer. Through experimentation, we achieved the highest power conversion efficiency of 4.49 % without antireflective coating, accompanied by Voc 0.795V, JSC 11.13 mA/cm2, and FF 0.507 when the 1st-Se thickness was 5 nm. Furthermore, the impact of decreasing Te/(Te + Se) near the TiO2 window layer on photovoltaic performance was theoretically predicted using modelling by SCAPS-1D. Overall, this work introduces a promising method for enhancing the formation of c-Se, improving adhesion between TiO2 and Se layers, and enhancing the power conversion efficiency of TiO2/Se heterojunction photovoltaic devices.

Enhanced thermally integrated Carnot battery using low-GWP working fluid pair: Multi-aspect analysis and multi-scale optimization

Thermally integrated Carnot battery (TICB) emerges as a promising technology for long-duration energy storage. This study aims to improve its multi-dimensional performance from the optimization design level, thereby promoting its competitiveness. Firstly, a refined system architecture is developed, integrating subsystem layout modification and advanced thermal integration mode. Sixteen potential working fluid pairs are formed by screening low-GWP refrigerants as drop-in substitutes for R245fa. Then, a comprehensive evaluation framework is established to characterize this technology from energy, exergy, and economic perspectives, and a collaborative optimization method is introduced to facilitate integrated optimization. Finally, a whole cycle cumulative exergy analysis is conducted to explore directions for further improvement. Results indicate that, compared to the basic architecture, the round-trip efficiency (RTE) of the proposed system is elevated by over 30%. The use of different alternative refrigerants in the charging and discharging cycles makes the TICB not only sustainable but also more efficient. The thermodynamic dilemma of determining the heat pump evaporation temperature disappears with a closed-type heat source. To maximize overall thermo-economics, sufficient heat pump subcooling and evaporator internal superheat are necessary, and the ideal storage temperature span and pinch point temperature difference of heat exchangers must be identified. The collaborative optimization displays that the first-rank working fluid pair is R1234ze(Z)-R1224yd(Z), with an RTE of 85.2%, a volumetric energy density of 3.10 kWh/m3, and a levelized cost of storage of 0.303 $/kWh, respectively. Furthermore, the RTE is highly sensitive to the insulation quality of storage tanks. A mere 2.5% performance degradation can lead to a 10% points decline in RTE. Internal exergy destruction is primarily caused by poor heat transfer matching, while external exergy loss mainly results from underutilized heat sources during non-charging periods. Therefore, we recommend the district heating network as the target heat source for the dual-period TICB. These achievements offer a valuable reference for the research and development of efficient, affordable, and sustainable TICB.

A comprehensive review and comparison of cooling techniques for photovoltaic panels: An emphasis on experimental setup and energy efficiency ratios

This study delves into exploring and comparing various cooling technologies for PV panels, with a special focus on revealing the harmful effect of excessive heat absorption on solar energy efficiency. Effective temperature management and dissipation of excess heat are essential to protect the integrity of PV panels and improve power generation. With a strong emphasis on the importance of experimental setups, this comprehensive research examines the methodologies and cooling methods used across a wide range of experimental studies, illustrating the complexities of data collection and analysis. Supported by schematic illustrations depicting various experimental setups, this study demystifies the complexities inherent in distinct PV cooling methods. Furthermore, the research extends beyond experimentation to include a comprehensive examination of the energy and economic aspects associated with various cooling technologies, including the calculation and presentation of energy efficiency ratios. It is worth noting that the results confirm the superiority of passive cooling techniques, including heat sinks (43 %), PCM (25), evaporation techniques (36 %), and spray cooling systems (54 %), in contrast to active cooling methods, as indicated by their net energy efficiency ratios. Passive cooling is advantageous for its low maintenance and cost-effectiveness, whereas active cooling, though effective in hot climates and enhancing PV efficiency, incurs higher initial costs and maintenance requirements. The novelty of this research lies in its detailed classification of cooling techniques and the specific materials used for each method, coupled with a thorough examination of the measuring tools employed. Furthermore, this study includes a comprehensive comparative analysis based on energy and economic aspects, alongside the advantages and disadvantages of each cooling technique. These invaluable insights hold the potential to revolutionize the development of efficient and dependable cooling strategies for PV systems, thereby elevating the feasibility and sustainability of solar energy as a pivotal cornerstone in our future energy landscape.

Effects of Utilizing Black Glass Balls, Phase Change Material, and Fins on the Performance of the Single-Slope and Single-Basin Solar Water Distiller under Climate Conditions of Mosul City: An Experimental Study

The present investigation involves an experimental examination of incorporating rectangular fins, black glass balls as porous media, and phase change material (PCM) above the absorber surface to improve the effectiveness of the single-slope and single-basin solar water distiller system, known as MSS-FPPCM. Data was gathered in November and December 2023 in Mosul City, Iraq. The performance was evaluated with and without the addition of porous media at varying water depths. The results indicated that the highest basin water temperature, PCM temperature, productivity, and efficiency were achieved when utilizing fins, black glass balls, and PCM. The maximum temperatures recorded for water basin and PCM, productivity, and efficiency were 55°C, 55.4°C, 1.01 kg/m2, and 30.83%, respectively, at a water depth of 3cm. The results highlight the significant impact of porous media, phase change material, fins, and water depth on heat exchange, evaporation, and heat transfer rates.

Triple-enhanced Raman scattering sensor based on superhydrophobic/-philic microsphere platform and heating evaporation assisted for high-sensitivity detection

The ability to detect molecules in small volumes of highly diluted solutions is crucial for applications such as food quality and safety, environmental monitoring, biomedical diagnostics, and so on. The primary concern lies in the sensitivity and efficiency of detection technology. In this work, an ultra-sensitive surface-enhanced Raman scattering (SERS) detection strategy is presented, which is based on superhydrophobic/-philic microsphere SERS (SSM-SERS) platform and heating evaporation assisted for high-sensitivity detection. Relying on the heating-assisted evaporation, the evaporation efficiency of the droplet is increased by 378.5 times, and the deposition area after evaporation is reduced by 10.4 times, leading to the extremely high detection efficiency and further enrichment of the target molecules. When the microspheres array approaches the superhydrophobic/-philic (SH/SHL) substrate, the optical-plasmonic hybrid structure is formed, enhancing light-matter interactions and resulting in an improvement of the Raman signal. The optimized SERS sensor is capable of detecting Rhodamine 6 G (R6G) at the femtomolar level (10−16 M), with a sample volume of only 5 μL and an enhancement factor of 3.29 × 109. Considering the misuse of fish drugs, malachite green (MG) and methylene blue (MB) were chosen to validate the performance of SERS sensor. These findings highlight the consistent high sensitivity of the SERS sensor, offering valuable insights for applications in food safety and related fields.

A Screening Apparatus for Comparing the Fouling Resistance of Heat Exchanger Surfaces

AbstractFouling is a challenge in many processes, especially in heat exchangers and evaporators. Even though many treatments have been developed to mitigate fouling on metallic surfaces, no standardized method exists to compare equipment based on its antifouling performance. In this work, a screening apparatus is presented, which allows to compare samples of treated metallic surfaces based on thermal fouling resistance. A parameter screening and a ranking of three differently treated metallic surfaces using two model substances, namely, whey protein concentrate (WPC) and calcium sulfate, are demonstrated.

Effects of the droplet size and engine size on two-phase kerosene/air rotating detonation engines in flight operation conditions

The numerical and experimental research of rotating detonation engines is usually conducted in ground environmental conditions. Although many breakthroughs have been made, there are still deficiencies in understanding engines operating in real flight conditions. In order to reveal the effect of engine size and initial kerosene droplet size on the rotating detonation engines in flight conditions, the Eulerian-Lagrangian model is adopted, and a series of two-phase kerosene/air rotating detonation cases are simulated in the conditions of Mach 5 and 24 km altitude. When 5 μm and 10 μm droplets are adopted, the RDE behaves like gaseous rotating detonations with clear cellular structures. When the 20 μm and 30 μm droplets are adopted, the rotating detonation waves tend to be divided into two layers and form the λ-shaped shock structure. The results indicate that droplet size and engine size influence detonation wave propagation and flow field mainly through droplet heat absorption and evaporation height. Increasing the engine sizes can promote the two-phase rotating detonation and broaden the initial diameter range capable of obtaining rotating detonation waves. However, as droplet size increases, the fresh mixture layer becomes stratified, with an upper layer predominantly comprising fuel vapor and a lower layer of fuel droplets, which results in an λ-shaped shock structure at the detonation front. The flight operation condition brings in differences in features such as detonation wave height and velocity deficit. The detonation height in flight conditions is higher than that in ground conditions. The most velocity deficit in flight conditions observed in our study is below 15 %, which is lower than the results (22.5 %) in ground operating conditions. These results indicate that the optimal design of the rotating detonation engine must consider the real operation conditions and the effect of engine sizes and droplet sizes.

Heat transport and load response characteristics of a molten salt solar tower power station engaged in peak regulation

Power system flexibility can be improved effectively, if the advantages of the peak shaving ability of molten salt solar tower power (STP) plant can be developed and utilized. In this paper, the heat transport and load response characteristics of the molten salt STP plant in the regulation process are studied, aiming at serving the development of the regulation method in the rapid peak regulation process. The steam generation system and turbine system models of a 50 MW STP station are established. Two load regulation methods and operation modes are used to investigate the inertia and delay effects of heat transfer and evaporation, as well as load response characteristics during the actual regulation operation, including steam generation system following (SF), turbine following (TF), constant pressure operation (CP), and sliding pressure operation (SP). The results show that when the plant load is reduced by 10% Pe at the rate of 3% Pe/min, the heat transfer of salt/water and the evaporation process of water in the whole regulation process have a 250 s delay compared with the load. The larger heat storage characteristics of the plant help to improve the load response speed. The load response speed of the plant is faster in SF mode. TF mode is beneficial to the safe operation of the plant. Considering the operational safety of thick-wall component, the recommended running mode is the collocation of SF and SP mode, TF and CP mode. The results show that the load change rate of 10% Pe/min is permittable under TF and CP modes. The conclusion of this paper lays a foundation for the formulation of a peak regulation strategy for molten salt STPs.

Electrothermal-assisted all-weather solar steam generator based on hydrogel implantation strategy

Using solar energy to treat sewage is a feasible scheme to alleviate the shortage of water resources and reduce carbon emissions. However, the fluctuation of sunlight intensity poses a great challenge to the stability of the treatment process, which hinders its application in the actual water treatment scene. Herein, based on the adhesion of hydrogel, an electrothermal-assisted all-weather solar steam generator with sandwich structure was synthesized through hydrogel implantation strategy, in which polyacrylamide hydrogel with thermal grease-modified heating wires was implanted as the middle heat conduction layer, the photothermal evaporation layer as the upper layer and the waste heat evaporation layer as the bottom layer. The electrothermal assisted solar evaporator (EASE) perfectly achieves the superposition of photothermal and electrothermal effects, and can achieve high interfacial water evaporation performance under extremely low auxiliary working voltage. Applying a low voltage of 2 V to both ends of the evaporator can achieve a high evaporation rate of 4.58 kg m−2h−1 under 1 solar irradiation, which is similar to the sum of the evaporation rate under only 1 solar illumination (2.22 kg m−2h−1) and a 2 V voltage input (2.26 kg m−2h−1). More interestingly, the suitable thickness of the hydrogel layer not only ensures the transfer of heat between layers, but also weakens the heat loss caused by the water flow effect. The implantation strategy ensures the stability of the water structure and inhibits the hydrogen reaction of electrolytic water in the electrothermal process. This work provides an important theoretical and practical reference for the preparation of all-weather solar interface water purification equipment.