Effect Of Supercharging Research Articles

Adsorption of surfactant molecules onto the surface of colloidal particles: Case of like-charged species

Mixed systems of nanoparticles and surfactants have a broad range of applications from consumer products and medicine to inkjet printing and oil recovery. The interparticle interactions can be tuned in presence of surfactants and are dependent on surface charge of both species, particle’s wettability, surfactant solubility, and solution conditions such as electrolyte concentration and pH. The case of oppositely charged particles and surfactants has been extensively examined in the literature, primarily to tune the wettability of particles. In contrast, the behavior in systems of like-charged species such as negatively charged particles and anionic surfactants remains poorly understood, with conflicting findings reported in previous studies on the adsorption of surfactants. By conducting a comprehensive investigation, in this study we shed light on the factors that influence the adsorption of surfactant onto the particle surface, both promoting and preventing it, and unravel the underlying mechanisms governing such behavior. Silica nanoparticles were used as the negatively charged particle, sodium dodecyl sulfate (SDS) was used as the surfactant and potassium nitrate was used as the salt, while the pH was adjusted by potassium hydroxide and nitric acid, to investigate the effect of surfactants on the surface characteristics of the silica nanoparticles under various operating conditions. The zeta potential of particles along with the solution conductivity were obtained via mobility measurements. Using this information, the solution’s Debye length and the particle’s surface charge density were estimated. It was found that interpreting the outcome solely based on the zeta potential data might not reveal the adsorption of SDS onto the particle surface as no supercharging effect could be detected in some cases. However, shifting the perspective to charge density shows that SDS increased the particles charge density for pH values in the range of 2–5, corresponding to the pH conditions at which vicinal and geminal silanol groups are dissociated. This effect was more pronounced at moderate total ionic strengths between 1 and 10 mM, where SDS activity was found to be higher and the Debye length was sufficiently short. The increase in the particle’s charge density was attributed to the tail-down adsorption of SDS onto the particle surface via entropically-driven interactions. These findings offer valuable insights into like-charged mixed particle/surfactant systems and bring clarity to the scientific community regarding this complex and previously inconclusive topic.

Pulsating pressurization of two-phase fluid in a pipe filled with water and a little gas

Although two-phase flows containing gas and water have received extensive attention, the pulsating pressurization effect of a two-phase fluid in a pipe is unclear and the influence of the gas-phase content has not been revealed. This paper discusses the pulsating pressurization of such a two-phase fluid. First, the two-phase Navier–Stokes equations are derived and an algorithm is developed based on MacCormack's method. The reliability of the algorithm is examined and validated using Poiseuille's theory and existing experimental two-phase flow data. Finally, the influence of several key factors is discussed, including the gas-phase fraction and pipe slenderness. Our results show that a significant pulsating supercharging phenomenon occurs when the gas-phase fraction is less than 10−3. When the gas-phase fraction is greater than this critical value, the pulsating supercharging effect decreases significantly with the increasing gas-phase fraction. The equivalent elastic modulus of the two-phase fluid rapidly decreases as the gas-phase fraction increases, and the pressure disturbance is absorbed by the gas bubbles, causing an apparent weakening of the pulsating supercharging effect. Thus, decreasing the gas-phase content can enhance the pulsating supercharging effect. The pipe slenderness has a very limited influence on the pulsating pressurization process, and the maximum reduction is only 7.3% for slenderness ratios of up to 2000. Moreover, we derive and propose a new mathematical expression for the inlet boundary that is applicable to gas–liquid two-phase flows. To our knowledge, this paper extends the pulsating pressurization range from the single-phase to two-phase fluid for the first time and reports different physical phenomena and regularity. The present research clarifies the pulsating pressurization phenomenon in two-phase flows, providing a valuable reference for pulsating pressurization design.

Pore pressure evaluation of formation testing while drilling under supercharged conditions

Formation Testing While Drilling (FTWD) to evaluate pore pressure has significantly progressed in geo-energy exploitation. However, with the increasing number of unconventional reservoirs, this technology is facing some challenges owing to the common occurrence of supercharging in the vicinity of boreholes. The pressure response of FTWD under supercharged conditions is different from that of non-supercharged; thus, conventional methods — such as Pressure DrawDown (PDD), Pressure BuildUp (PBU), and Formation Rate Analysis (FRA) — cannot be used to determine the original pore pressure. In this paper, a new mathematical model of the FTWD pressure response under supercharged conditions is proposed by considering the time-dependent filter cake, supercharging, skin, geometry, and storage effects. The calculated results indicated that when the formation permeability was lower than 5 mD, the supercharging effect on the pressure response of FTWD cannot be neglected. The pressure response curve of FTWD under supercharged conditions only includes three segments: the fast pressure drawdown stage, pressure buildup stage, and recovered pressure decreasing stage. It is also found that the pressure response in the later stage is independent of the withdraw withdrawal pumping modes and the pressure response curves are nearly the same. Based on the pressure response characteristics, a novel method to evaluate the original pore pressure was proposed. Case studies show that the proposed method can obtain the correct virgin pore pressure after a few iterations and the relative error is lower than 0.2%. Compared with conventional methods, this method is more accurate and saves time; thus, it can be used to evaluate the original pore pressure of FTWD under supercharged conditions.

An analytical solution for spherical fluid flow modeling in porous media with non-uniform initial pressure considering the supercharging effect

Abstract The diffusivity equation is a partial differential equation (PDE) which can be used for fluid flow modeling in porous media. Determining reservoir parameters from pressure data (i.e., pressure transient analysis) is one of the most important steps in the process of field development. This initial evaluation can be used to make decisions about future developments. Wireline Formation Testing (WFT) is one of the most popular techniques for parameter estimation and has received significant attention in recent years. The main problem plaguing WFT is a phenomenon known as the “supercharging effect,” which essentially refers to mud invasion, and this, in turn, alters pressure distribution across the system. In this study, an analytical solution for fluid flow modeling in spherical coordinates with non-uniform initial pressure is presented. This new procedure takes into account the effect of mud invasion, or, in other words, the supercharging effect. The accuracy of this derivation was validated using previous semi-analytical solutions (the Laplace method) in addition to field data. New type curves and dimensionless parameters, which can be used for pressure transient analysis, are also proposed. This procedure is applied to the WFT data that was obtained from an oil field in the south of Iran, and an excellent agreement (less than 10% error) was observed. In addition, there is considerable uncertainty regarding the radius of investigation for spherical flow. This is important as this parameter greatly affects the applicability of WFT. The analytical derivation of this study was used to determine a reasonable value for this parameter as well.

Supercharging of Proteins by Salts during Polarity Reversed Nano-Electrospray Ionization.

Supercharging is beneficial in many ways to the analysis of proteins by mass spectrometry (MS). In this work, a novel supercharging method was developed. It made use of our previously developed ionization technique: namely, polarity reversed nanoelectrospray ionization (PR-nESI) for the ionization of proteins. Supercharging of proteins was achieved by just adding 1-10 mM of a salt to the sample, such as sodium chloride (NaCl). The charge state of proteins obtained by our method was significantly higher than that by nano-ESI with 1% (v/v) acetic acid (HAc). Different kinds of salts were investigated. Salts withstrong acid anions were capable of supercharging proteins, including chlorides, bromides, iodides, and nitrates. The signal intensity and signal to noise ratio ( S/ N) of proteins were increased at the same time. Phosphates were also found to have a supercharging effect, due to the fact that phosphoric acid was a medium-strong acid. In comparison, salts with weak acid anions had no supercharging effect, such as carbonates, sulfides, acetates, and formates. The species of the salt anion was critical to the supercharging effect, while the species of the salt cation showed little influence on the supercharging effect. Investigations were made into the mechanism of our method. The supercharging effect was caused by interactions between protein molecules and salt anions, as well as the influence of protons. The present work offered us an alternative way for the supercharging of proteins. The use of common salts for supercharging made the procedure more convenient. The concentration of salts needed for supercharging was much lower than those conventionally used for supercharging reagents. Taking into consideration the fact that many biological samples are buffered with phosphates and chlorides, these samples could be directly supercharged by our method without any additional additives. Furthermore, as many salts are nontoxic and can easily be found in a chemical laboratory, the use of salts for supercharging would be a much more practical and economical choice. In addition, the present work also furthered our understandings about the mechanism of supercharging, as well as electrospray.

Influence of intake parameters on combustion and emission performance of dual-fuel Marine diesel engines

We in order to study the influence of intake parameters on the combustion and emission of natural gas-diesel dual-fuel Marine engine, AVL_FIRE simulation software was used to build a high pressure cycle model of combustion chamber based on 4190ZLC-2 Marine medium-speed diesel engine. The accuracy of the model was verified by comparing the simulation data with the cylinder pressure curve obtained from bench test. The influence of intake parameters on combustion and emission performance was studied by model simulation. The results show that the combustion quality can be improved by increasing the intake temperature, and the power performance and economy can be improved by appropriate intake temperature. Increasing the intake pressure has the effect of supercharging, appropriately increasing the intake pressure can obtain better power and emission, and can also avoid the rough operation of dual-fuel diesel engine and reduce the noise

Effects of Supercharging and EGR on Diesel Combustion with C4/C5 Bio-alcohol Blended Fuels

Effects of Supercharging and EGR on Diesel Combustion with C4/C5 Bio-alcohol Blended Fuels

A numerical investigation on the influence of EGR in a supercharged SI engine fueled with gasoline and alternative fuels

Alternative fuels are mostly extracted from renewable resources, and their emission levels can be lower than those of traditional fossil-based fuels. A computational fluid dynamics (CFD) method is utilized to investigate the effects of exhaust gas recirculation (EGR) and initial charge pressure on the emissions and performance of a SI engine. The engine is fueled separately by gasoline and some of potential alternative fuels including hydrogen, propane, methane, ethanol and methanol. The results of simulation are compared to the experimental data. In all validation cases, experimental and numerical results were observed to have good agreement with each other. The calculations are carried out for EGR ratios between 0% and 20% and four cases of initial pressure have been mentioned: Pin=1, 1.2, 1.4, 1.6bar. The effect of EGR on NOx emission of methane is more than other fuels and its effect on IMEP of hydrogen is less than other fuels. From the viewpoints of emission and power, 10% of EGR seems to be the most desirable amount. The most noticeable effect of supercharging is on gasoline unlike hydrogen, which seems to be affected the least. The comparison of results shows that hydrogen due to its high heating value and burning without producing any carbon-based compounds such as HC, CO and CO2 is an ideal alternative fuel compared to the other fuels.

Hydrogen and Ethanol as Potential Alternative Fuels Compared to Gasoline under Improved Exhaust Gas Recirculation

In the present study, a computational fluid dynamics (CFD) method have been utilized to investigate the effects of exhaust gas recirculation (EGR) and initial charge pressure by means of using a supercharger on the emissions and performance of a SI engine. This engine is fueled separately by gasoline and two potential alternative fuels, hydrogen and ethanol. The results of simulation are compared to the experimental data. There is a good agreement among the results. The calculations are carried out for EGR ratios between 0% and 20% and four cases of initial pressure have been mentioned: Pin= 1, 1.2, 1.4, 1.6 bar. The effect of EGR on NOx emission of hydrogen is more than others while its effect on IMEP of hydrogen is less than others. From the viewpoints of emission and power, 10% of EGR seems to be the most desirable amount. The most noticeable effect of supercharging is on gasoline unlike hydrogen that seems to be affected the least. The comparison of results shows that hydrogen due to its high heating value and burning without producing any carbon-based compounds such as HC, CO and CO2 is an ideal alternative fuel compared to the other fuels.

Predicting supercharging effect in suction line in inverter rotary compressor

Predicting supercharging effect in suction line in inverter rotary compressor

Effect of liquid invasion damage and supercharging on wireline formation tester measurements in tight gas reservoirs

Wireline formation testing and measurement of true formation pressure can provide essential knowledge about the reservoir dynamic characteristics. In tight formations, a reliable determination of pressure and mobility gradients is challenging because of the tight nature of formation rock. Due to the very low reservoir permeability, the mud cake across wellbore is often ineffective in preventing filtrate invasion, thus causing the measured pressure to be higher than actual formation pressure as a result of supercharging effect. Wireline formation testing measurements are also influenced by the effects of filtrate invasion and capillary pressure, as the measured pressure is pressure of drilling fluid filtrate, the continuous phase present in the invaded region around wellbore. As a result, the measured pressure might be different to true formation pressure. This effect is more noticeable in tight gas reservoirs due to capillary pressure effect. This paper looks into estimation of true formation pressure and evaluates the effect of filtrate invasion damage and supercharging on wireline formation tester measurements in tight gas reservoirs. Numerical simulation approach is used to build the reservoir model based on data acquired from a tight gas reservoir. The model undergoes water injection followed by gas production from different testing points along the wellbore, and the corresponding pressure gradients are plotted to check for pressure matching with that of the formation fluid in the virgin region. The results indicate the significant effects of supercharging, reservoir characteristics, capillary pressure and liquid invasion damage on wireline formation pressure measurements in tight gas reservoirs.

The effect of supercharging on performance and emission characteristics of C.I. Engine with diesel-ethanol-ester blends

Biofuels like ethanol, biodiesel, have attracted attention of people worldwide and proved to be the successful fuel alternates to petroleum products. In the present investigation, the effect of supercharging is studied on the performance of a direct injection diesel engine using ethanol diesel blends with palm stearin methyl ester as additive. The performance of the engine is evaluated in terms of brake specific fuel consumption, thermal efficiency, exhaust gas temperature, un-burnt hydrocarbons, carbon monoxide, nitrogen oxide emissions, and smoke opacity. The investigation results showed that the output and torque performance of the engine with supercharging was improved in comparison with naturally aspirated engine. It is observed that the brake thermal efficiency of ethanol diesel blends was higher than that of diesel. With supercharging brake thermal efficiency is further improved. Brake specific fuel consumption of ethanol, ester and diesel blends are lower compared with diesel at full load. Further reduction in brake specific fuel consumption is observed with supercharging. Nitrous oxide formation seems to decrease with ethanol, ester and diesel blends. Hydrocarbons and carbon monoxide emissions are more with ethanol, ester and diesel blends with supercharging slight reduction in those values are observed.

Interactions between large colloids and surfactants

The interfacial adsorption of an anionic SDS and a nonionic surfactant C12E5, above the cmc onto submicron-sized, negatively charged silica particles in aqueous solution has been investigated by using electrokinetics, conductometry and static light scattering. It was found that both surfactants are prone to being adsorbed onto the silica/water interface. Addition of C12E5 to the silica dispersion leads to a decrease in mobility. This reduced surface charge causes a decrease in the stability of the silica particles. Surprisingly, the addition of SDS brings about an increase in the negative electrophoretic mobility of the anionic silica particles, leading to a super-charging effect. Subsequent addition of C12E5 gives rise to even higher negative electrophoretic mobilities. This unexpected hyper-charging effect can only be understood as a cooperative effect based on mixed micelles of C12E5 and non-adsorbed SDS. Not so unexpectedly, the sequence of surfactant addition was found to be decisive, as quite different results are obtained when C12E5 is added before SDS.

過給・スワール強度・燃料噴射圧力がディーゼル噴霧の発達および燃焼に及ぼす影響

過給・スワール強度・燃料噴射圧力がディーゼル噴霧の発達および燃焼に及ぼす影響

Effects of Supercharging, EGR and Variable Valve Timing on Power and Emissions of Hydrogen Internal Combustion Engines

Effects of Supercharging, EGR and Variable Valve Timing on Power and Emissions of Hydrogen Internal Combustion Engines

Compressor performance of two-stage turbocharging system

To study the performance of high and low stage compressors and that of the system as a whole, a two-stage turbocharging system was matched, and a special two-stage turbocharging system test bench was built. For each test curve, the speeds of the two stage turbochargers were adjusted to the fixed data, and a compressor performance experiment was performed. The results showed many differences between the corrected mass flow and the actual mass flow of the high pressure (HP) stage compressor. To find out the actual supercharging effect of the two-stage turbocharging system, it is better to adopt the actual mass flow. The two-stage turbocharging system in this paper has much higher efficiency under most operating conditions if the pressure ratio assignment is 1:1. The system can get very high supercharging pressure when the speeds of the two stage turbochargers are rather low, which ensures the system’s security and reliability.

Effect of comprex supercharging on diesel emissions

Diesel engine emissions are highly complex mixtures. They consist of a wide range of organic and inorganic compounds distributed among the gaseous and particulate phases. Particulates and NO x emissions are the important components of the Diesel exhaust. The composition of Diesel exhaust varies considerably, depending on engine type, operating conditions, fuel, and lubricating oil. In this research, the effects of supercharging, which is one of the engine operational parameters, on Diesel emissions have been investigated. For this purpose, a comprex, CX (pressure wave supercharger) was designed and manufactured and then matched to an indirect injection Diesel engine. During the engine tests, the emission parameters (CO, SO x , NO x and smoke density) have been observed and measured for different pulley ratios at full load conditions. The results showed that CX supercharging may be an alternative way of NO x reduction with some modifications.

Effect of supercharging on the performance of a DI Diesel engine with cotton seed oil

Diesel engines are the prime movers for heavy duty vehicles used in the transportation and agricultural sectors. Diesel engines meet their energy requirement from stored fuels, i.e. petroleum products. The twin problems of both depletion of scarce resources and atmospheric pollution caused by vehicles run on petro-products are enticing researchers to find a viable and immediate alternative to fossil fuels. The physical and combustion properties of vegetable oils are close to those of petro-Diesel fuel, and in this context, vegetable oils can stand as an immediate candidate to substitute for stored fuels. Vegetable oils are produced from processing the seeds of various plants and, thus, are renewable in nature. Sustainable development of a country depends on the extent that it is managing and generating its own resources. This also helps in conservation of depleting non-renewable petro-products. However, due to inherent high viscosity and low volatility, vegetable oils would pose problems, such as fuel flow and poor atomization, and constrain their direct use in engines without any modifications. In the present investigation, the effect of supercharging is studied on the performance of a direct injection Diesel engine with the use of untreated cotton seed oil under varying injection pressures (IPs). The performance of the engine is evaluated in terms of brake specific fuel consumption (BSFC), exhaust gas temperature and smoke density. It is observed that when cotton seed oil is used as a fuel, there is a reduction in BSFC of about 15% when the engine is run at the recommended IP and supercharging pressure of 0.4 bar (g) in comparison with the engine operation run under naturally operated conditions. The investigation revealed that cotton seed oil, in general vegetable oils, can best be utilized if supercharging is employed at the recommended IP of the engine.