Search

With the rapid development of perovskite solar cells (PSCs), PSCs without electron transport layer (ETL) structure have been reported one after another, but the efficiency is low. In this work, a tin-based ETL-free structure of perovskite solar cell is introduced. In order to explore the internal influencing factors of the device with ETL-free structure, we used SCAPS-1D (Solar Cells Capacitance Simulator) to simulate the device and adjust the appropriate physical parameters to approximate the results reported in the experiment. The simulation results show that the thickness of the absorption layer, defect density, operating temperature and band gap have different effects on the performance of the device, and the best absorbent layer thickness is 600 nm. When the operating temperature exceeds 300 K, the performance parameters will decrease, and the band gap is best controlled at about 1.3 V. It should be pointed out that defect density is the main culprit that seriously affects device performance. When defect density exceeds 1015cm−3, power conversion efficiency (PCE) begins to decline significantly, and we need to pay more attention to defect density. At the same time, the effects of different interface defect layers (IDL) on device performance are simulated. It is found that when the defect density of the interface defect layer is too high, the asymmetry effect will appear. The interface defect layer IDL2 between the absorption layer and the hole transport layer (HTL) has a greater effect on the open circuit voltage (VOC), and the interface defect layer IDL1 has a greater effect on PCE. Therefore, it is necessary to pay attention to these defect layers to improve the VOC and PCE. Finally, based on ETL-free PSCs, we list HTL of different materials for reference, and provide new ideas for perovskite solar cells in the future.

Increasing power cycle efficiency is an important way to reduce the cost of the solar thermal power generation. The power generation system using a supercritical carbon dioxide (s-CO2) Brayton cycle has the advantages of high cycle efficiency, small equipment size and low corrosion. Then, low temperature waste heat generated by the s-CO2 Brayton cycle can be used as the low temperature heat source for multi-effect desalination. This paper discusses a s-CO2 Brayton cycle integrated with a multi-effect seawater desalination system. The heat input of the s-CO2 Brayton cycle is from a central-tower solar receiver. The residual heat of the s-CO2 Brayton cycle is the heat input of the multi-effect distillation system. The results show that the integration of multi-effect desalination system does not affect the s-CO2 Brayton cycle efficiency. With the increase of split ratio of the compressor, Brayton cycle efficiency increases and then decreases, and the water production decreases and then increases. With the increase of turbine inlet temperature, Brayton cycle efficiency increases while freshwater production varies insignificantly. After optimizing the design of the cogeneration system, solar thermal power efficiency is 24.04%, the cost of electricity generation can be reduced, the LCOE is 0.081$/kWh. by using the waste heat generated from the power cycle. realized electricity-water cogeneration, the fresh water production from 5-effect MED is 459m3/day, and the unit cost of freshwater UPC of 0.81$/m3.

The thermal and electrical performance of the photovoltaic-thermal (PVT) system still needs to be improved although the system has been widely applied. In this study, the performance of a multilayer-structured PVT system with phase change materials (PCMs) is investigated experimentally and numerically. The novel design of layout scheme of heat exchanger is introduced, and a detailed mathematical model of the heat transfer process and operational efficiency of the PVT system is developed. Subsequently, the temperature variation of the PVT system is simulated and verified by measurements based on an outdoor experimental system. According to the measurements and calculation by using a home-made MATLAB code, the characteristic temperature and efficiencies of the PVT system are predicted. The results show that the forecasted temperature variation of the PVT system agrees well with the practical system. The average electrical efficiency of the PVT system can increase by around 1% by using the heat exchanger with PCMs. Meanwhile, the thermal efficiency is raised due to the prolonged operation time. The composite PCM with 15% expanded graphite may enhance the comprehensive efficiency by 25.2%. Moreover, the database of the performance of practical PVT systems in East Shanghai is supplemented with measured and evaluated values.

A chemical-looping hydrogen generation technology (CLH) has considerable potential in renewable energy exploration because it can produce hydrogen and capture carbon dioxide at low energy. This study designs a novel system combining solar energy harvesting and chemical-looping hydrogen technology for hydrogen production, carbon dioxide capture, and power generation. The system is analyzed using commercial process simulation software. The effects of major factors including solar heating rate are investigated. When solar power absorbed by Fe3O4 solid particle flow is less than 132.75 kJ/mol, the yield of hydrogen and the mass fraction of the captured CO2 in the system increase with increasing solar heating rate. When solar power absorbed by Fe3O4 solid particle flow is larger than 132.75 kJ/mol, the yield of hydrogen and the mass fraction of the captured CO2 decrease with increasing solar heating rate. A set of particle energy storage equipment is added to the system to make sure stable operation given solar irradiance fluctuates. Finally, the yield coefficient X of hydrogen, H2(molar)/CH4(molar) in the system is stabilized at 3.8, the System energy efficiency η is stabilized at 79% and the mass fraction of captured carbon dioxide is stabilized above 93%.

Loop thermosyphon (LT) is a two-phase closed device that provides an alternative solution to overcome the freezing problem associated with the traditional photovoltaic/thermal (PV/T) system. The overall performance of a LT-PV/T system is significantly affected by volume-filling ratio. To reveal this effect, a prototype of the LT-PV/T system was designed and constructed in this paper; and long-term outdoor tests under 24%, 32%, 40% and 48% volume-filling ratios were carried out. The results show that the daily average photothermal performance of the LT-PV/T system presented a trend of increased first and then decreased with the volume-filling ratio increasing on the selected sample days. The highest performance was generated under the 32% filling condition. The solar evaporator had an even temperature distribution when the volume-filling ratio was no less than 32%; the temperature difference of the solar evaporator decreased with the volume-filling ratio increased, the values were 1.5 °C, 1.2 °C and 0.6 °C, respectively. Performances of the collector and system were linear fitted based on the outdoor tests, the fitting results showed that both of them shared the same variation trend, the optimum volume-filling ratio lied in between 32% and 40% of the whole system volume, but nearer to 32%.

To find a medium temperature phase change heat storage material with high thermal conductivity and heat storage ability, expanded graphite (EG) with high thermal conductivity is used as the carrier material, and the binary mixed molten salt of 88 wt% LiNO3–12 wt% NaCl is used as the phase change material (PCM). EG and PCM are uniformly dispersed by ultrasound crushing method. To get the right EG addition ratio, LiNO3–NaCl/EG composite PCMs (LNE) with EG mass ratio of 10 %, 15 %, 20 %, and 30 % are prepared by static melt adsorption method. The melting point, phase change enthalpy and other parameters of the composite material are tested and analyzed. The experimental results show that the melting temperature and the phase change enthalpy of LNE gradually decrease with the increase of EG mass proportion. For all LNE samples, the adsorption ratio of PCM exceeds 90 % to 95 %. The thermal conductivity of the PCM greatly improves with the increase of EG mass proportion. The thermal conductivity of the composites with 15 wt% EG is 6.532 W·m−1·K−1, which is about 3.7 times that of the binary mixed molten salt. The thermal conductivity increases with the increase of the apparent density. The composite PCM has stable performance. The 85 wt% LiNO3–NaCl/15 wt% EG composite PCM has the best overall performance.

Because of their unique and tunable photoluminescence properties, exceptional physicochemical properties, high photostability, biocompatibility and small size, Graphene quantum dots (GQDs) have received a lot of attention. However, insufficient investigations have been carried out on GQD fluids. In this paper, the properties of a prepared GQD fluid are studied experimentally, involving the physical stability, rheology, thermal conductivity, optical properties and corrosion characteristics. It is found that a highly physically stable GQD fluid could be easily achieved because the selected GQDs are well dispersed. It is also found that the addition of GQDs had a slight effect on the base fluid viscosity, but it could significantly increase the thermal conductivity of the fluid. In addition, the investigation of the optical properties shows that the GQD fluid exhibited high absorption to sunlight. The transmittance of ultraviolet and near-infrared light is close to zero. In contrast, the transmittance of GQDs to visible light is high at low weight concentrations, but significantly decreases with the increase of the proportion of GQDs. The corrosion characteristics of the copper and carbon steel samples in the selected GQD fluid or deionized water were experimentally investigated. It is found that the selected GQD fluid can greatly accelerate the corrosion of copper. However, nearly the same corrosion rate is observed for carbon steel in the GQD fluid as that in deionized water. The high stability, low viscosity, enhanced thermal conductivity and unique optical and corrosion properties allowed the GQD fluid to have excellent potential for applications in the energy sector.

In the paper, the flower-like Cu2O had been obtained in the distilled water under very low reaction temperature. This hydrothermal method provided a homogenous environment for the nucleation and growth of the Cu2O. The reaction temperature, time, solvent, and additives would affect the purity and morphology of samples. When the reaction temperature was greater than 90 °C, elementary copper appeared in the as-obtained sample. With the reaction temperature and time increase, the morphologies also had been changed. The changing process of these morphologies had also been discussed. When ethanol amine replaced some or all of the aqueous solution, the resulting product is pure copper. Meantime, the effect of copper sources and additives on purity and morphology of products were investigated. Finally, the optical properties and PEC properties of the flower-like Cu2O were studied. This paper provided a very simple and low cost method to synthesis of flower-like Cu2O, which would be of great potential for the synthesis of other metal chalcogenides.

In the present work, a numerical study is made on the fully-developed forced convective heat transfer of nanofluids in a curved square duct using Eulerian-Lagrangian two-phase approach. The curvature ratio of the duct is 0.02 and its hydraulic diameter is 8 mm. The Al2O3-water nanofluids contain spherical nanoparticles with particle diameter of 30 nm and volume fraction of 0.5%. Three different flow structures of nanofluids are obtained through the small perturbations generated by three different computers at the same conditions. The flow has a structural 2-cell, 3-cell or 4-cell at different Dean numbers and on different solutions, which leads to multiple non-uniform nanoparticle concentration distributions and multiple temperature fields. Multiple flow fields are symmetric in a low Dean number region and asymmetric in a high Dean number region, which leads to multiple symmetric (asymmetric) nanoparticle concentration distribution and temperature distribution fields, multiple symmetric (asymmetric) local Nusselt number and local friction factor along the outer wall at low De values (high De values), and finally lead to multiple mean friction factor and multiple mean Nusselt number. A significant enhancement of heat transfer (e.g. 23.79% at De of 335.2) can be achieved at the expense of a slight increase of flow friction (e.g. 6.84% at De of 335.2) in curved square duct through switching the solutions. This study could provide an explanation, from a new respect, for the inconsistent results of convective heat transfer of nanofluid in the literature.

This study presents a 3-dimensional numerical simulation of a flat-plate photovoltaic/thermal (PV/T) hybrid system using a nanofluid as the solar spectrum filter. A series of parametric studies have been carried out to investigate the module performance by employing different base fluid (water, therminol VP-1 and propylene glycol) - nanoparticle (Ag, Fe3O4 and SiO2) combinations. The present work explores the effects of different nanoparticle concentrations, volume flow rates of applied nanofluids, as well as the solar spectrum intensities on the energetic and exergetic performances of the proposed module. Merit functions for various basefluid or nanofluid based hybrid PV/T systems are also assessed in order to determine their economic feasibility. The results show that the suspension of nanoparticles into basefluids has a considerable influence on the radiative heat fluxes that are absorbed by each component of such system. The selection of basefluid-nanoparticle combination is dramatically affected by the desired energy form, based on the system energetic and exergetic performances. Besides, both the system energy and exergy efficiencies are improved with the increment of solar irradiance, whereas they have a counter tendency by increasing the volume flow rate of working fluid. The employment of liquid absorptive filters in such systems can realize a higher energy output which is 179%–240% of that of a stand-alone PV system.

With the rapid development of hydrogen production technology by using solar energy, the research of Solid Oxide Electrolysis Cell (SOEC) and Photovoltaic/Thermal (PV/T) system have become popular. A design scheme of hydrogen production system based on PV/T technology was proposed. The electrolytic cell combined photovoltaic panels, trough solar collectors and multiple heat exchagers to improve the overall efficiency of the hydrogen production system. The efficiency was predicted based on empirical models. The results showed that the hydrogen production efficiency of SOEC increased with increasing temperature and with decreasing current density. However, the balance between energy efficiency and hydrogen production rate of SOEC needed to be taken into account. The predicted hydrogen production efficiency of SOEC and overall system efficiency also agreed well with the results available in literature.

Irreversible magnetic loss exists in the operation of the wireless electric vehicle (EV) charging system, which will cause serious heating problems. Phase change materials (PCMs) is widely used and have a good performance in the field of thermal management. Aiming at the cooling of high-power wireless EV charging system, a set of PCM-based thermal management system is designed for the limited space using the special aluminum alloys with high permeability and high thermal conductivity. The heat flow density at the transmitter of wireless EV charging system is in the range of 0.5–0.75 W/cm2. The experiments study the temperature change at the transmitter under different heat emission conditions. The cooling efficiency and the heat transfer coefficient at the heat transfer surface are compared between the horizontal air flow through the cooling channel with and without PCM. The results show that the designed PCM-based thermal management system can meet the wireless EV charging system’s demand of cooling and the heat transfer coefficient varies with air velocities. Using PCM can ensure that the stable temperature of the heating plate does not exceed 80 °C under the long operation scheme with the ambient temperature of 20 °C. These can provide support for the PCM-based thermal management of wireless EV charging system.

In order to alleviate the peak shaving pressure of power grid and further improve the deep peak shaving capacity of coal-fired units, this paper applies staged heat storage to condensing units. Under the condition of constant boiler load, the heat of regenerative steam extraction is stored to reduce the electrical load output of the unit. Taking a 660MW ultra-supercritical unit as an example,30%THA,40%THA and 50%THA were taken as the initial conditions of heat storage respectively to discuss the peak shaving range and power regeneration efficiency of different extraction steam positions for heat storage. The results show that the “storage 1# HP heater extraction steam” scheme with “two-stage three tank” heat storage and release structure has the largest peak shaving range of 37.3%~56.9% under 50% initial conditions. When the “two-stage three tank” heat storage and release structure selects the “storage 1# HP heater extraction steam ”scheme under 40% initial working condition, the “power regeneration efficiency” reaches the highest——78.3%. And the “power regeneration efficiency” of “two stage three tank” storage structure are always higher than the “single-stage” storage structure.

Long chain n-alkanes had been employed as the matrix of solid-liquid composite phase change materials due to the high latent heat. In this paper, paraffin-based composite PCM were constructed. To obtain the effects of the ratio of epoxide and hydroxyl groups on functionalized graphene, Molecular dynamics simulation had been used to calculate several composite systems. According to the obtained results, the interfacial thermal resistance surprisedly decreased by 48.68% when the ratio of epoxide and hydroxyl groups was 0.5. And the order parameter in x and y-directions showed the correlation on the interfacial thermal resistance. In terms of the melting point, the composite systems containing the functionalized graphene had lower value in chosen contrasting systems. The present findings were expected to reveal some intriguing thermal behaviors of the graphene/paraffin composite phase change materials with different ratios of epoxide and hydroxyl groups.

The study of radiation property of particles is of great significance in the field of solar thermo-chemistry. In this study the randomly dispersed particle system is obtained by the KBr tablet method, and the transmittance of activated carbon particle systems in 0.4–25 μm wavelength are measured by the spectrophotometer and FTIR to obtain their radiation property. The extinction coefficient of the particle systems and the efficiency factor for extinction of single particle are calculated through experimental data. The results show that the activated carbon particles have higher absorption ability in the visible light spectrum. Above investigation will not only be beneficial to the simulation of solar thermo-chemistry hydrogen production process, but also provide an experimental basis for inverse calculation of optical constants of the activated carbon particles.

Based on the typical meteorological year data of Shanghai city, annual performances of solar water heating (SWH) system and photovoltaic/thermal (PV/T) system are comparatively analyzed under three different cases. The results show that when only solar energy is used, the effective day number of SWH system is more than PV/T system under the same case every month; for the PV/T system, heat loss at the nighttime dissipates most of the absorbed solar energy under the continuous heating mode considering the nighttime heat loss case; initial water temperature determines system electric efficiency. On the whole, PV/T system offers competitive performance only under the auxiliary heating mode, no matter from the points of primary efficiency and static payback period.

In a photovoltaic–thermal (PVT) solar collector, a small percentage of the absorbed solar radiation can be converted into electricity and the rest become heat. The heat could be collected through various working mediums. It is of great practical significance to study PVT system and improve its performance further. In this study, an experimental PVT system using MPCM (Microencapsulated Phase Change Material) slurry as the cooling medium was designed and established. The comprehensive performance of the PVT system was studied. The measured electrical and thermal efficiency of the PVT system using MPCM slurry or tap water under various conditions were compared. Moreover, the MPCM slurry was also used as the working fluid in an outdoor PVT system. The practical performance was compared with those of a traditional water-cooled PVT system and a similar system with PCM layer. The results showed that increasing the flow rates of the MPCM slurry could reduce the temperature of PV cell and improve the thermal and electrical efficiency. The performance of the present PVT system using MPCM slurry is better than that using pure tap water or water with a PCM layer. The average electrical efficiency and the maximum thermal efficiency of the system can effectively increase by 0.8% and 13.5% respectively. The slurry containing low concentration MPCM could enhance the performance, indicating the feasibility of the actual application in solar PVT system.

It is cost effective to manufacture a reflective surface of a solar parabolic trough concentrator in a parabolic cylinder shape by pure bending of a flat sheet. However, the surface manufactured by such an elastic bucking is only a coarse approximation of a parabola, which is not precise enough for meeting the demand of a high quality concentrator. A novel design concept was proposed to remove this error by applying an external force on both edge of a sheet, together with two additional forces: the edge torsion force and the pressing force. The optimal position and magnitude of two additional forces were figured out among various conditions, thereby a theoretically maximal concentration ratio up to 115 was found. Prototypes and engineering realizations of this method were also presented. This method provides a very attractive approach for low cost and high efficiency solar energy solutions.

In the traditional PV/T collector, the temperature of thermal energy is always limited by the operation temperature of PV cells. Such a low-temperature thermal energy can hardly meet the demand in industrial application. To breakthrough the temperature limitation, a concentrating PV/T collector with fluid-based spectral splitting filter is developed in present work. The oleylamine solution of Cu9S5 nanoparticle is adopted in the filter to harvest the moderate-temperature heat. The performance of the collector is investigated by an outdoor experimental system. The results indicate that the PV efficiency of Si cell itself can be improved when the Cu9S5 nanofluid is employed as the optical filter in the collector. The maximum overall efficiency of present PV/T collector is 34.2%, which is 17.9% higher than that without a filter. The present collector has successfully obtained thermal energy with a temperature higher than 100 °C, which verifies the potential of Cu9S5 nanoparticles in fluid-based spectral splitting technique. Moreover, the particle concentration has a significant influence on the performance of hybrid PV/T system. The ratio of heat to electricity in PV/T system can be adjusted by changing the particle concentration to meet the requirements in various applications. In addition, the glass cover surrounding outside of the optical filter can improve the thermal efficiency, but it also increases the optical loss of the system due to the reflection on the surface of glass. Therefore, to realize higher performance, it is necessary to employ the glass with anti-reflection layer in the collector.

The high-power wireless charging system for the electric vehicle (EV) generates irreversible magnetic loss and quantities of heat during the charging process. Using thermal management with phase change material (PCM) can reduce the temperature rising rate and ensure the operation safety. A thermal management optimization for a 6.6 kW wireless EV charging system with PCMs was studied. The mathematical model of the heat transfer process in the charging system with thermal management was developed. It was solved by a MATLAB procedure and verified by an experimental measurement. A concept of effective time was proposed as the optimization index to evaluate the performance of the thermal management system. The results indicated that the thermal conductivity of the PCM needed to be improved for a better thermal performance. The modified PCM as paraffin with expanded graphite (EG) was adopted and the optimum thickness and thermal properties were obtained. The effective time by using the optimal PCM layer was 3 and 1.2 times that by using the original PCM layer for the charging system with 5% and 10% energy loss, respectively. The optimal layer can keep the temperature of the charging system below 60 °C in long-term operation.

PV windows provide thermal insulation, daylight use and power generation simultaneously. Present investigation aimed to evaluate the energy performance of 3 types of PV windows under 5 climates of China, and particularly to clarify the influences of transmittance and orientation on its energy performance. The present work involves: (i)the experimental testing that had been carried out; (ii)validation of the EnergyPlus model of natural ventilated double PV (NVDPV) window; (iii) prediction of the energy performance of the 5 PV windows under typical climates of China based on the validated model; (iv) applicability discussion of the PV windows under different climates and influence of transmittance and orientation. The results reveal the highest energy saving rate obtained by NVDPV window in the 5 cities. The NVDPV window integrated PV glass with transmittance of 10% delivered better energy performance than the window with transmittance of 5% under climates of Harbin, Beijing, Shanghai and Shenzhen. The south facing windows achieved least building electricity consumption under the climates of Harbin, Beijing, Shanghai, and Lhasa. Exceptionally, the east facing windows achieved least electricity usage under the climate of Shenzhen. The achievements from the present work provide a reliable criterion for the optimized design of PV windows.

The red water-soluble AgInS2 nanocrsytals (AIS NCs) were synthesized by one-step hydrothermal method. The effects of reaction time and molar ratio of precursors on the bandgap and fluorescence properties of AIS NCs were studied by UV–Vis absorption spectra, photoluminescence (PL) spectra. The experimental results indicated that the fluorescence peak of AIS NCs showed red-shift from 651 nm to 691 nm with the increase of reaction time. The full width at half maximum (FWHW) of AIS NCs obtained at 12 h was very narrow with 18.5 nm. When the reaction temperature and time were set to 200 °C and 12 h, the PL peaks of AIS NCs changed from 696 nm to 670 nm and 735 nm with the increase of indium concentration. In addition, the effect of In concentration on the optical band gap and PL peak was opposite. The optical bandgaps were 1.29 eV, 1.76 eV, and 1.51 eV, respectively. The photocatalytic H2 production performance was studied. The results indicated that the all AIS NCs obtained at different conditions showed high hydrogen production efficiency (>1000 μmol g−1•h−1). Finally, this method is very simple, safe, and easily controlled, and the position of fluorescence peak is adjustable, which shows that AIS NCs obtained in the paper have great application prospects.

Interaction potential plays a vital role on the friction. Potential energy of two contacts directly determines on the friction force. However, many mathematic models proposed, always abandon the instantaneous status during sliding to devote to a weighted average over lateral force, which might miss some information about friction behavior. In this work, the relation among potential energies, separation distances of two contracts, and positions in the sliding direction are studied to evaluate the instantaneous friction characteristics. Two hydrogenated diamond surfaces are used as the examined model. The results show that a watershed between positive and negative friction forces locates at the position with the minimum adsorption energy. A rapid decrease in potential energy occurs near the 2.5 nN external force, where the friction coefficient approaches zero at each position in the sliding direction. Therefore, a novel method may be developed to greatly reduce the friction coefficient between two surfaces by adjusting the contract pressure.

In order to improve the absorption rate of polycrystalline silicon thin film cells, an inverted pyramid structure was constructed and the metal nanoparticles were dispersed in the inverted pyramid structure. The absorption rate of the designed composite structure was improved by utilizing the LSPR effect generated by the metal particles, and the change of the absorption rate under different conditions was studied by changing the type, volume fraction and H/P ratio of the periodic structure in the composite structure. By using FDTD software to simulate, this paper finds that the designed inverted pyramid structure has a maximum absorption rate of 20% in the 0.4∼0.55um band. In the composite structure, the dispersed Ag nanoparticles have the best absorption rate in the 0.55∼0.8um band; The volume fraction of the particles in the inverted pyramid structure is found to increase slowly with the increase of volume fraction in a certain band. By changing the ratio of the depth of the inverted pyramid structure to the length of the period, it is found that as the ratio increases, the whole absorption rate will increase to some extent.

In order to reduce the moisture content of flue gas in coal-fired power plants, this paper puts forward a novel spraying system with upward spraying and downward gas flow (ST-UD). And the heat and mass transfer models of ST-UD in fluent were validated against experiment data. Then orthogonal simulation experiment was carried out to get the relationship between the four influence factors and the two evaluation indices. Through the range analysis and trend analysis, it can be found that the influence degree and the influence trend of factors on evaluation indices. The conclusion of this paper provides a reference for the heat-transfer performance optimization of other spray towers.

The NOx emission of gas turbine is a key factor of air pollution. It is still a challenge to realize low-NOx generation for all the gas turbines with diverse types of combustors and operation schemes. In this study, a three-dimensional simulation of the internal flow and combustion in a double-swirler annular combustor of a heavy-duty gas turbine was carried out. The realizable k-e turbulent model and finite rate/eddy dissipation combustion model were employed for the numerical calculation. The effects of the swirl number and temperature of the inlet premixed gas flow on the thermal performance and the relationship between the velocity-temperature field synergy and the thermal NOx formation were investigated on the basis of field synergy principle. The results indicated that the change of the outer swirl number had a greater impact on thermal NOx generation than the change of the inner swirl number. The velocity-temperature field synergy in the combustor became better as the inlet swirl number or the inlet gas temperature increased. This synergy had a correlation with the thermal NOx generation. The formation rate of thermal NOx in the combustor should be controlled with the optimized velocity-temperature field synergy rather than the sole reduction of inlet gas temperature by considering the required thermal uniformity and capacity. The adopted field synergy is a promising concept to evaluate the thermal related performance of combustor. The obtained results on the generation characteristics under various inlet conditions may guide the design and operation of gas turbine combustors.

Phase change material (PCM) has important applications in the field of thermal energy storage due to its characteristic that the temperature is basically unchanged during the endothermic and exothermic processes. At the same time, it helps to achieve heat supply/demand balance and reasonable energy distribution. Nitrates are widely used as mid-temperature phase change material, but they have relatively low phase change latent heat than chlorine salt. In order to get a kind of material with high phase change latent heat, 50 wt% LiNO3–45 wt% NaNO3–5 wt% KCl (LNK) ternary mixed molten salt is prepared with static mixing melting method. Meanwhile, LNK/expanded graphite (EG) composite phase change materials are prepared with ultrasound smashing method. The experimental results show that the addition of KCl changes the performance. The melting temperature of LNK reduces 20.6 °C and its phase change latent heat increases 19.9 J/g, compared with 43 wt% NaNO3–57 wt% LiNO3 binary nitrate mixture. The thermal properties and thermal stability of the materials are tested and analyzed. The experimental results show that both the ternary phase change material and the composite phase change materials have high phase change latent heat and chemical stability. EG has greatly increased the heat conductivity of the composite phase change materials. The thermal conductivity of 85 wt% LNK/15 wt% EG composite phase change material increases by 778% compared to LNK at 20 MPa forming pressure.