Effect Of Injection Temperature Research Articles

Understanding the emission behaviour of 0D Cs4PbBr6 perovskite nanocrystals at room temperature

We report 0D Cs4PbBr6 perovskite nanocrystals emitting at room temperature, synthesized by hot injection technique. Effect of injection temperature (TR) on the emission of Cs4PbBr6 nanocrystals (NCs) has been studied. High-quality NCs are synthesized in the 100 °C–180 °C temperature range. Pure phase Cs4PbBr6 nanocrystals are formed at lower temperatures (TR = 100 °C), while at higher temperatures, CsPbBr3 impurity phase appears along with Cs4PbBr6. Cs4PbBr6 nanocrystals emit blue light with broad emission spectra in the 400–500 nm wavelength range, while a green emission from CsPbBr3 impurities at 520 nm wavelength is observed. The emission spectra from Cs4PbBr6 NCs shows multiple radiative centers in the 400–500 nm range, unaffected by the change in excitation wavelength. The emission of pure Cs4PbBr6 is attributed to charge transfer states of Pb2+ ions and surface states incorporated by presence of ligands on NC surface. Further, it is to be emphasized that the Cs4PbBr6 perovskite NCs are highly stable and maintain their emission even after two years of synthesis.

Effects of Injection Temperature and Pressure on CO2 Storage Capacity and Safety in a Sloping Formation

Effects of Injection Temperature and Pressure on CO₂ Storage Capacity and Safety in a Sloping Formation

Impact of CO2 sequestration on pressure systems in saline aquifer: Simulation of differential pressure evolution in the caprock-reservoir

CO2 sequestration in the saline aquifer is one of the most promising means of geological sequestration, and the realization of safe CO2 sequestration without leakage is the common goal of sequestration projects. Mature continental sedimentary basins typically have a long drilling and production history, and several wellbores inevitably penetrate the saline aquifer. These wellbores have been identified as risky locations for CO2 leakage. Scale-up CO2 injection can cause large-scale perturbations to the saline aquifer pressure system, affecting the sealing integrity of wells within the sequestration site. Considering that differential pressure is a key driver of wellbore leakage, this paper establishes and validates a three-dimensional cap-reservoir model to simulate the evolution of the differential pressure between the cap-reservoir due to CO2 sequestration. The simulation results show significant differences in the magnitude and rate of pressure buildup in the cap and reservoir during injection and in the rate of overpressure dissipation after stopping injection. These differences caused the dynamic evolution of the interlayer pressure difference. They formed peaks in the injection and stopping stages, and the peak in the injection stage was higher than in the stopping stage. The peak decreases as an exponential function with increasing distance from the injection well. In the constant rate injection mode, the peak rises linearly with increasing injection rate, and the effect of injection temperature on the peak can be neglected. A sensitivity analysis of reservoir hydrogeological parameters was done. From the perspective of controlling differential pressure, an ideal saline aquifer should be characterized by deep burial, low salinity, high permeability, and large effective pore space. This study is significant for CO2 sequestration site optimization and CO2 leakage risk control.

Study on effect of injection temperature on shear strength of the direct bond between polyphenylene sulfide and anodized aluminum alloy

A simple and environmentally friendly technique has been proposed to form a composite structure of high interfacial bonding strength between polyphenylene sulfide (PPS) and aluminum alloy (Al). The Al substrate is modified through anodization and enlarging treatments. The influences of injection temperature on the anodic aluminum oxide film surface on the interfacial bond strength of the formed PPS-Al is discussed. The results revealed that when the injection temperature of PPS was set at 310°C, the bonding strength increased to 18.0 MPa. The adhesive strength exhibits a clear dependency on the injection temperature. At higher injection temperatures, PPS exhibits higher flowability and better penetration into nanoscale pores, resulting in a strong interlocking between PPS and anodized aluminum alloy.

Modeling rock damage during the long-term production process for hot dry rocks: Effects of additional conductivity on the production performance and economic efficiency

Hot dry rocks (HDRs), as an essential renewable energy source, its development has received widespread attention, especially for heat extraction. The fracture is the main seepage and heat transfer channel of circulating fluid in dense HDR reservoirs, and its conductivity evolution significantly affects the production performance. Most existing studies have focused on the change of fracture conductivity under elastic deformation without considering the additional conductivity induced by rock damage. However, the additional conductivity may have significant implications for rational design and timely adjustment of the production scheme. Therefore, a three-dimensional model at the field-scale is established, and it is used to analyze the effect of additional conductivity on production performance and economic efficiency. To simplify the calculation, the actual forms of damage are equivalent to the macroscopic physical evolution of the matrix. Results show that the rock is mainly tensile failure affected by thermal stress during production. The occurrence of damage will increase the reservoir permeability and porosity, reduce Young’s modulus, and then reduce the differential pressure and production temperature, with a maximum reduction of 2.21 MPa and 14.21 °C in the control case, respectively. The effects of injection temperature, Young’s modulus, and injection mass flow on the production performance are significant, followed by Poisson’s ratio. In contrast, production pressure and fracture initial permeability had less influence. The maximum differential economic benefit of the control case is up to 2.289 million RMB. This research proves the necessity of damage study during the long-term production of HDRs.

Numerical analysis of temperature effect on CO2 storage capacity and CH4 production capacity during the CO2-ECBM process

Temperature is a key factor affecting the CO2 injection efficiency and CH4 production efficiency, so it is of great significance to clarify the evolution diagram of temperature change during the CO2-ECBM process. In this study, the crushed soft coal seam with low permeability in Huainan coalfield was taken as the research object. Firstly, the fully coupled mathematical models of CO2-ECBM process were constructed, and the influence of temperature field on CO2-ECBM process was emphasized. Secondly, the evolution law of CO2-ECBM process at different time was revealed. Then, the effects of injection temperature and initial temperature on the CO2-ECBM process were analyzed. Finally, the evolution mechanism of reservoir temperature during the CO2-ECBM process was illustrated, and the effect of temperature on temperature field of CO2-ECBM process was further illustrated. The results show that the longer the displacement time, the CH4 concentration gradually decreased, and the CO2 concentration gradually increased. The area where the temperature changes are more concentrated focuses on the vicinity of CO2 injection well, which are mainly determined by the dominant reaction of adsorption and desorption reactions of binary gas. Reservoir temperature and permeability are positively and negatively correlated with injection temperature, respectively. Both CO2 storage capacity and CH4 production capacity increase with the increase of injection temperature, and the sensitivity of CO2 storage capacity to temperature was greater than that of CH4 production capacity. With the increase of displacement time and injection volume, the effective displacement radius increases, but the increment of influencing radius gradually decreases. The lower the initial temperature of coal reservoir, the larger the influencing radius, and which increases with the increase of displacement time. CO2 storage capacity and CH4 production capacity decrease with the increase of initial temperature. Young's modulus and Poisson's ratio can effectively change the reservoir strength. CO2 storage capacity and CH4 production capacity decrease with the increase of Young's modulus, and increase with the increase of Poisson's ratio. This study can support the engineering landing of CO2-ECBM technology in crushed soft coal seam with low permeability, and promote the realization of China's “Dual Carbon” strategic goal.

Mechanical Properties of Weld Lines in Injection-Molded Carbon Fiber-Reinforced Nylon (PA-CF) Composites.

Weld lines are a common defect generated in injection molding, which apparently affects the performance of final products, but the available reports on carbon fiber-reinforced thermoplastics are still rather few. In this study, the effects of injection temperature, injection pressure, and fiber content on the mechanical properties of weld lines were studied for carbon fiber-reinforced nylon (PA-CF) composites. The weld line coefficient was also calculated by comparing specimens with and without weld lines. The tensile and flexural properties of PA-CF composites significantly increased with the rise of fiber content for specimens without weld lines, while injection temperature and pressure demonstrated slight influences on mechanical properties. However, the existence of weld lines had negative influences on the mechanical properties of PA-CF composites due to poor fiber orientation in weld line regions. The weld line coefficient of PA-CF composites decreased as fiber content increased, indicating that the damage of weld lines to mechanical properties increased. The microstructure analysis showed that there were a large number of fibers distributed vertically to flow direction in weld lines regions, which could not play a reinforcing role. In addition, increasing injection temperature and pressure facilitated fiber orientation, which improved the mechanical properties of composites with low fiber content, while weakening composites with high fiber content instead. This article provides practical information for product design containing weld lines, which helps to optimize the forming process and formula design of PA-CF composites with weld lines.

Thermal and Postural Effects on Fluid Mixing and Irrigation Patterns for Intraventricular Hemorrhage Treatment

Intraventricular hemorrhage is characterized by blood leaking into the cerebral ventricles and mixing with cerebrospinal fluid. A standard treatment method involves inserting a passive drainage catheter, known as an external ventricular drain (EVD), into the ventricle. EVDs have common adverse complications, including the occlusion of the catheter, that may lead to permanent neural damage or even mortality. In order to prevent such complications, a novel dual-lumen catheter (IRRAflow®) utilizing an active fluid exchange mechanism has been recently developed. However, the fluid dynamics of the exchange system have not been investigated. In this study, convective flow in a three-dimensional cerebral lateral ventricle with an inserted catheter is evaluated using an in-house lattice-Boltzmann-based fluid–solid interaction solver. Different treatment conditions are simulated, including injection temperature and patient position. Thermal and gravitational effects on medication distribution are studied using a dye simulator based on a recently-introduced (pseudo)spectral convection–diffusion equation solver. The effects of injection temperature and patient position on catheter performance are presented and discussed in terms of hematoma irrigation, vortical structures, mixing, and medication volume distribution. Results suggest that cold-temperature injections can increase catheter efficacy in terms of dye distribution and irrigation potential, both of which can be further guided by patient positioning.

Analysis of variance of injection moulding process parameters and clay particles size effects on impact strength, shrinkage and warpage of polyethylene/kaolin clay composites

A correlation effect between particle size of kaolin clay and injection moulding process parameters on impact strength, shrinkage and warpage of high-density polyethylene/kaolin clay (HDPE/KC) composites was carried out using analysis of variance (ANOVA). Kaolin clay with particle sizes of < 75, 75–106 and 106–150 μm was used. The process parameters that were taken into consideration were injection temperature, packing pressure and packing time. In general, experimental results showed that the impact strength and shrinkage of the HDPE/KC composites clearly depended on the injection temperature. However, no clear dependency of the warpage on the injection temperature was observed. Furthermore, clay particle size showed to have an influence only on the shrinkage of the composites, where smaller clay particle size led to injected composite parts with relatively less shrinkage. ANOVA showed that the effect of injection temperature on shrinkage of composites containing clay particle sizes of < 75 and 106–150 μm was statistically significant (p = 0.01 and 0.04, respectively). However, the effect of injection temperature on shrinkage of the composite made with clay having particle sizes of 75–106 μm was not significant (p = 0.07). ANOVA also indicated that the injection temperature effect on the impact strength of composites that contain clays with particle sizes of < 75 μm and 75–106 μm was significant (p = 0.03 and p = 0.01, respectively), whereas the injection temperature effect on the impact strength of the composite containing clay with a particle size of 106–150 μm was not significant (p = 0.17). Contrary to shrinkage and impact strength, the effect of the studied parameters on the warpage was not statistically significant, which was in good agreement with the experimental observations.

Reaction mechanism and reservoir simulation study of the high-temperature nitrogen injection in-situ oil shale process: A case study in Songliao Basin, China

China’s oil shale reserves are 739.1 billion tons and 45 per cent of which are in Songliao Basin. Therefore, a pilot project is conducted in Songliao Basin, aimed at technical preparation for commercial in-situ oil shale processes production. Because N2 is readily accessible and has no damage to the formation, the high-temperature nitrogen injection in-situ conversion process (HNICP) is the most basic convection heating technique, which is used in the pilot project. In this study, the Wellington reaction model is adjusted to describes the pyrolysis behavior and characteristics of shale in Songliao Basin, China. Based on the geological data and production date of the pilot project in Songliao Basin, a simulation model matching the production test scheme is established to investigate subsequent production performance and the evolution of reservoir physical properties for 550 days. Finally, the effect of injection temperature, total organic carbon (TOC), and enclosing area on the recovery factor is analyzed. The results show that the oil production rate can be divided into four stages for the HNICP of oil shale. In the third stage, prechar accumulation is very severe in the main fracture. However, the prechar accumulation relieves the heat short problem in the main fracture. The high temperature is beneficial to the production of oil, HC, and prechar. The formation plugging in the low TOC shale formation is more serious. Because of the spontaneous imbibition of oil in the formation away from the main fracture, the small enclosing area is beneficial to the production of oil.

Experimental analysis of supercritical-assisted atomization

Supercritical CO2 is used in supercritical-assisted atomization (SAA) systems to promote the atomization of nanoparticle suspensions in powder generation in pharmaceutical, electronics, and coating applications. Due to the sensitivity of the mixture properties to the operational conditions, the SAA process is not fully resolved to date. This study experimentally investigates the underlying mechanisms behind SAA utilizing CO2 or N2 as the assisted-atomization fluid (CO2-A or N2-A) using high-speed imaging and laser diffraction techniques. The effects of injection temperature, pressure, and gas-to-liquid ratio (GLR) are explored, and empirical droplet size models are developed. It is found that the primary breakup of CO2-A is governed by the emergence of the near-nozzle gas bubbles originated from the dissolved CO2, which expand radially and squeeze the liquid due to the inertial forces. As a result, the edges of the liquid core become thinner and deform into relatively long ligaments that further break up into droplets. CO2-A exhibited a shorter liquid length, wider spray angle, and smaller droplet size compared to N2-A. The discrepancies observed in the breakup process are mainly attributed to the higher solubility of CO2 in water and lower surface tension of the CO2–water system. The smallest droplet size distribution and the narrowest droplet size distribution are detected for CO2-A injected at the critical pressure of the CO2–water binary system where the solubility of CO2 in water significantly rises. Linear instability analysis indicates that both shear and acceleration that indirectly incorporate the experimentally observed bubble expansion are the main factors driving the instabilities.

A numerical study on jet characteristics under different supercritical conditions for engine applications

Fuel injection is one of the key factors that influence the energy conversion efficiency and emission level of engines. In this study, supercritical injection and mixing under different conditions were investigated using large eddy simulation method. Real-fluid thermodynamic models based on the Peng-Robinson equation of state, including the volume-translation method, were established, and the adjusted pressure implicit split operator algorithm was developed to handle solution instability due to thermodynamic nonidealities. Density variations, potential core lengths, spreading rate, and turbulent velocity fluctuations were analyzed. The effects of injection temperature and ambient pressure on supercritical jet disintegration were studied. The results show that both high injection temperature and elevated ambient pressure can facilitate jet mixing, and the potential core length and spreading rate are sensitive to the injection temperature near pseudo-boiling point. The pseudo-boiling process, which results in a large density gradient and isobaric heat capacity in the jet surface, delays the shrinkage of the radial boundary of the potential core and leads to small spreading angles of jets. The turbulent velocity fluctuations reveal significant anisotropy in the mixing layer of supercritical jets, and a large density gradient resulting from pseudo-boiling behavior damps radial turbulent velocity fluctuations at the surface of jets.

Jet breakup behavior of liquid carbon dioxide for coal transport applications

In this study, the spray patterns of different fluids exiting pressurized chamber through the nozzle were observed and compared. The effects of injection temperature and pressure on jet velocity and liquid carbon dioxide (LCO2) breakup were investigated. When the liquid was expelled from the chamber (45 bar) to the atmosphere through nozzle, the 1st- wind-induced jet breakup regime for H2O and the atomization regime for LCO2 were observed. Three different breakup regimes of LCO2 ranging from normal atomization to Rayleigh breakup were observed depending on the velocity, which can be explained by changes of the Reynolds number in Reynolds–Ohnesorge diagram. As the downstream pressure decreased (with increasing velocity), the choked flow was formed due to the phase change at the flash boiling point. The transition to choked flow moved to higher pressure differences with decreasing injection temperatures, indicating the delayed phase change.

Injection characteristics of near critical and supercritical kerosene into quiescent atmospheric environment

The injection of RP-3 aviation kerosene at near and above critical conditions into a quiescent atmospheric environment is experimentally investigated with special emphasis on the effects of injection temperature and pressure on the jet characteristics of shock structure and phase transition. Visualization of the near-field shock/jet structure is performed using Schlieren imaging. Results show that fuel condensation occurs when supercritical RP-3 is injected at near critical temperature. At the supercritical injection conditions investigated, ideal-gas-like expansion and internal shock structures are observed. A RP-3 surrogate is used to determine the thermodynamic phase diagram to reveal the phase transition during the injection processes. The characteristics of the Mach disk are further presented and discussed. It is found that the location and size of the Mach disk as well as jet expansion angle increase with increasing injection pressure. Furthermore, specific heat ratios and compressibility factors of RP-3 surrogate and N2 are evaluated to analyze their differences in Mach disk diameter and jet expansion angle; it is shown that the compressibility factor is the primary factor that deviates the jet structure of RP-3 from that of ideal-gas N2.

Experimental investigation on heat transfer of n-pentane spray impingement on piston surface

Fuel spray impingement on piston surfaces is a concern because it can cause particulate exhaust emissions from gasoline direct injection (GDI) engine. Transient heat transfer plays an important role that directly influences liquid film evaporation and its lifetime. In this paper, the effects of injection temperature, injection pressure, piston temperature and impact distance on n-pentane spray impingement heat transfer were fully examined. Results showed that increasing the piston temperature could increase the rate of heat transfer with a larger surface temperature reduction and a higher heat flux, which led to a shorter liquid film lifetime on the piston surface. Increasing the fuel injection temperature helped to improve atomization of the fuel spray, reduce the penetration distance and mitigate impact, which in turn led to reduced surface cooling and less liquid film on the piston surface. A decrease in impact distance and an increase in injection pressure both caused an increase in surface temperature reduction and heat flux but a decrease in the liquid film residence time. The dimensionless heat flux in terms of Biot and Fourier numbers presented a high similarity during the rapid cooling stage. A dimensionless correlation was formed to quantify this fast time-varying heat transfer behaviour.

Correlation of injection moulding parameters with mechanical and morphological aspects of natural fibre reinforced thermoplastics

AbstractThe mechanical behaviour of fibre reinforced composites depends – amongst other things – on the morphological structure. This in turn is greatly affected by the processing conditions. In this study a 10 weight % flax fibre reinforced high density polyethylene composite is prepared by extrusion compounding followed by injection moulding. The effect of injection temperature, speed and rotational screw speed on the morphology of fibres and matrix are studied and related to the tensile and impact behaviour of the composites. Results indicate that fibre length is easily affected by all parameters under consideration. Whereas a higher injection temperature allows the preservation of fibre length, an excessive increase in temperature, however, leads to their thermal degradation. Increased injection and rotational speeds further introduce excessive shear stresses on the fibre, causing their breakage, similarly leading to reduced mechanical performance. Matrix structure is mainly affected by the injection temperature, where its increase leads to the reduction in the degree of crystallinity and thus also a decrease in tensile strength. Other processing parameters prove to have minor effect on matrix morphology.

A numerical model for predicting distributions of pressure and temperature of superheated steam in multi-point injection horizontal wells

In order to make full use of the advantages of superheated steam (SHS), SHS injection in multi-point injection wells (MPIW) is proposed in this paper.Firstly, a mathematical model comprised of SHS flow model in inner tubing (IT) or long tubing (LT) and annulus, transient heat transfer model in oil layer is established. Secondly, type curves of SHS flow in MPIW is obtained by finite difference method on space and the iteration technique. Then, the effect of injection temperature on distributions of thermophysical properties of SHS in MPIW is discussed in detail. Results show that: (a) When the heat exchange between IT and annulus is taken into consideration. SHS temperature in IT has a decrease while SHS temperature in annulus has an increase. (b) With the help of MPIW, heating effect at both heel and toe points of the horizontal wellbores can be enhanced. (c) While the increase of SHS temperature certainly benefits the formation heating effect through the increase of both SHS temperature and superheat degree, the following decrease of SHS pressure in annulus will lead to the decrease of SHS absorption rate.This paper unravels some intrinsic flow characteristics of SHS in MPIW, which has a significant impact on the optimization of SHS injection parameters and analysis of heat transfer law in MPIW.

Flexural properties and morphology of microcellular-insert injection molded all-polypropylene composite foams

Single-polymer composite foams or all-polymer composite foams have been developed with further reduced weight, good interfacial adhesion and enhanced recyclability. All-polypropylene (PP) composite foams were prepared by the insert injection molding combined with microcellular injection molding. Flexural properties of the all-PP composite foams were reported and compared with solid PP, all-PP composites and PP foams. In comparison with solid PP, the 4.23% weight reduction, 16.52% increase of flexural strength and 20% increase of flexural modulus were achieved by the all-PP composite foams produced at the injection temperature of 220 °C and injection speed of 40 mm/s. Especially, the all-PP composite foams could have lower weight but higher flexural strength than the all-PP composites without foaming. The effect of injection temperature and injection speed on the flexural properties of all-PP composite foams was investigated to explore the optimum processing parameters for balancing good interfacial adhesion and weight reduction. Morphology properties were also investigated. The effect of processing conditions on the cell size and cell density of the all-PP composite foams was analyzed.

Metal acetate based synthesis of small-sized Cu2ZnSnS4 nanocrystals: effect of injection temperature and synthesis time

The metal precursor reactivity is shown to tune the Cu2ZnSnS4formation mechanism, and a synthesis with preferential formation of small-sized nanocrystals is demonstrated.

Influence of injection temperature and pressure on the properties of alumina parts fabricated by low pressure injection molding (LPIM)

The quality of ceramics parts made by powder injection molding (PIM) method is influenced by a range of factors such as powder and binder characteristics, rheological behavior of feedstock, molding parameters and debinding and sintering conditions. In this study, to optimize the molding parameters, the effect of injection temperature and pressure on the properties of alumina ceramics in the LPIM process were thoroughly studied. Experimental tests were conducted on alumina feedstock with 60vol% powder. Injection molding was carried out at temperatures and pressures of 70–100°C and 0.1–0.6MPa respectively. Results showed that increase in injection temperature and pressure and the resulting increase in flow rate leads to the formation of void which impairs the properties of molded parts. The SEM studies showed that injection at temperature of 100°C results in evaporation of binder components. From the processing point of view, the temperature of 80°C and pressure of 0.6MPa seems to be the most suitable condition for injection molding. In addition, the effects of sintering conditions (temperature and time) on the microstructure and mechanical properties are discussed. The best final properties were found using injection molding under the above stated conditions, thermal debinding and sintering at 1700°C during 3h.