As alternative jet fuels continue to be developed, their impact on combustor performance remains of utmost importance. Alternative jet fuels generally contain few aromatics and differ in alkylated compositions, yielding different chemical and physical properties from those of conventional jet fuels; understanding how these property differences impact combustor performance near limiting conditions is important in certifying their use in blending with petroleum derived fuels or as complete substitutes. Ignition and extinction properties that are associated with Lean Blowout (LBO) are areas of focus for jet fuel certification as they are important safety metrics bounding combustor stability. Previous results for 23 different test fuels in a referee combustor show a strong correlation of Lean Blowout (LBO) with fuel Derived Cetane Number (DCN). This previous study involved fuels with compositions similar to conventional fuels. However, fuels with properties differing significantly from conventional fuels were found to have a weaker correlation with DCN and higher LBO equivalence ratios overall. The surrogate fuels and blends that show the largest discrepancy from the earlier correlation were blends involving highly volatile, low DCN components such as iso -octane prevalent in the early stages of distillation, and less volatile, high DCN normal alkane components such as n -hexadecane, prevalent in the final stages of distillation. Thus, significant differences in fuel reactivity along the distillation curve from those of conventional petroleum derived fuels appeared to exhibit differing LBO character. From these observations, three hypotheses, preferential vaporization, relative droplet lifetimes, and thermal quenching, are proposed and investigated by utilizing the available data. Using normalized power law regressions, distillation simulation methods and Quantitative Structure Property Relation (QSPR) results, the DCN at 34% distillation recovery show a stronger correlation with LBO than the DCN determine for the fuel itself. In this paper, we apply findings to propose fuel compositions to investigate the noted hypotheses by utilizing reactive low molecular weight molecules and a less reactive high molecular weight fuel. The suggested fuel to stress test this hypothesis is a blend of 30 (molar)% n -heptane and 70 (molar)% Gevo Alcohol-to-Jet (ATJ), which is essentially composed of (primarily) 2,2,4,6,6 iso -dodecane and isocetane. If preferential vaporization is significant, then this fuel should be more stable than the “DCN-Law,” i.e. fuels are no more stable than the corresponding DCN allows, would predict.

A method for the speed matching of the second rotor (R2) with equal power for two rotors was proposed to avoid the overload of the second motor under low flow rate and the rapid decrease in pressure-rise and efficiency of R2 under high flow rate. The speed matching of two-stage rotors is proposed and analyzed to improve the stability margin of the counter-rotating fan (CRF). The fan performances during constant speed operating and during the speed matching operating are presented and discussed using experimental research. The results show that, the speed matching of R2 operating decreases the load of R2 under low flow rate and increases the pressure-rise and efficiency of R2 under high flow rate. Thus, the efficient working range and the blocking condition margin are increased. Reducing n 1 and increasing n 2 under low flow rate can regulate the position of unstable working line leftward without reducing the pressure-rise of the fan. Thus, the stability margin of the CRF is expanded.

Renewable energy has a significant role to play in helping the world achieve the greenhouse gas emission reduction necessary to achieve the pathway to a 2°C increase in global temperature. Electricity generation from wind and solar resources can contribute immensely to the decarbonization of power generation, but these resources are intermittent. High penetration of intermittent renewable power generation can cause grid stability and control issues for network operators, with fast response fossil fuel power plant necessary to provide security of supply and maintain grid stability. Increasingly natural gas-fueled distributed power generation is being installed to provide the necessary grid support. However, hybrid power plants comprised of a fossil fuel power generating system, a renewable power generation system and energy storage can provide both the low CO 2 electricity required to meet environmental constraints, and the despatchability and stability required by grid operators. Integrated Solar Combined Cycle Power Plants (ISCCs), comprising a Concentrated Solar Power plant and a natural gas fired combined cycle plant, have the potential to simultaneously reduce fossil fuel consumption, provide secure, highly predictable electricity generation, and reduce the cost of integrating renewable energy into a power system. While a number of ISCCs have been built at a larger scale (above 150MW power output), the concept has rarely been adopted for smaller scale distributed power applications. In addition, the traditional ISCC concept uses a steam bottoming cycle, which consumes water, and often locations where distributed ISCC could be utilized suffer from a scarcity of fresh water. This paper evaluates whether replacing the steam bottoming cycle with an Organic Rankine Cycle (ORC) alternative can provide a simpler, lower cost distributed ISCC solution that can be utilized on smaller and island grid systems, or mini- and micro-grids, to provide an affordable, water-free, low carbon power generation system.

In this paper, a novel nodalized reduced order model (NROM) has been developed to analyze the linear stability in a heated channel using supercritical water (SCW) as a coolant. The presented reduced order model is developed based on the two-phase flow system approach. The model is much simplified, which reduced the requirement of computational efforts and resources. In the heated channel, the SCW’s density shows a dramatic downfall near the pseudo-critical temperature, based on which it has been divided into n number of nodes. The one-dimension partial differentiation conservation equations of energy, mass and momentum are used and have been linearized by a small perturbation applied on its steady-state solution. These PDEs are converted into the corresponding time-dependent, nonlinear ordinary differential equations (ODEs) by using weighted residual method applied under some appropriate assumptions and approximations. These sets of ODEs (n+1 equations) are then solved analytically by using a state space approach to capture the stability boundary (SB) in terms of trans-pseudo-critical phase change number ( N tpc ), pseudo-subcooling number ( N spc ) by applying a constant external pressure drop (Δ P tpc ) condition across the channel. The NROM results are found to be in good agreement with the methodology and have been verified by numerical simulation. To extend this as a nonlinear stability analysis, the different types of the Hopf Bifurcation regime are also reported.

A series of experiments were performed on a vertical EV burner with a constant coflow air of 873 L /min to generate turbulent lean premixed flow in order to study the impact of the addition of Acetylene/Argon mixture to the liquefied petroleum gas (LPG) on the temperature field and flame structure. The fluidics mechanism was inserted at a fixed position inside the entry section of the EV burner assembly. The flow rates of fuel (LPG/C 2 H 2 / Ar) and air were measured using calibrated rotameters. The different volume ratios of the fuel constituents (at a specified fuel flow rate) were admitted via three solenoid valves at the entry section of each stream prior to mixing and monitored using a labview program. The axial temperature profiles at different operating conditions were measured using a bare wire Pt-Pt -10% Rh (type S) thermocouple of wire diameter 250 μm. Flame images were obtained — before and after fluidics insertion — using a high resolution Canon 6D 20MP digital camera. The selection of the different considerated cases was based on flame stability. The experimental program aims at identifying and analyzing the changes in flame characteristics (flame length, axial profiles of mean gas temperature, NOx concentration and overall combustion efficiency) resulting from the insertion of fluidics while considering different proportions of the fuel constituents) (including pure LPG, as a reference case). In all experiments flame stabilization was ensured. The results obtained indicate the following: it was noticed that in most cases of pure LPG only, and other mixtures the images shows increase in both the length and luminosity of the flame as a result of higher degrees of swirl due to the fluidics insertion while the temperature profiles of the different flames were changed. It was indicated that NOx trend was decreased by 52% while the combustion efficiency was improved by 2.5%.

Increasing the share of intermittent renewable energy sources in a power system poses challenges in terms of increased net load variability and maintaining grid stability and security. Operational flexibility of coal-fired power plants in China has played an essential and promising role in accommodating these nonequilibrium in the power grid. In the study, focusing on condensate throttling coupled with thermal storage tank measures, dynamic simulations of an entire 660 MW supercritical coal-fired power plant were developed via the GSE software. Then, the dynamic characteristics of main thermodynamic parameters and output power were described and compared, and operational flexibility performances of these measures were discussed. It turns out that: when condensate water flowrate decreases, the largest power ramp rate, power capacity, and energy capacity are 12.68 MW min −1 , 12.76 MW, and 1084.70 MJ, respectively, and when condensate water flowrate increases, the largest power ramp rate, power capacity, and energy capacity are −5.49 MW min −1 , −5.65 MW, and −695.94 MJ, respectively, which means condensate throttling without thermal storage tank measure is more suitable for power-up regulation than power-down regulation, but the shortest duration time is 130 s, which will restrict the operational flexibility regulation. However, coupling with thermal storage tanks, the deaerator water level can maintain a longer time. Meanwhile, at feedwater bypass 60% coupled with thermal storage tank, the largest power ramp rate, power capacity, and energy capacity are −3.62 MW min −1 , −3.81 MW, and −897.31 MJ, respectively, and at condensate water bypass 60% coupled with thermal storage tank, the largest power ramp rate, power capacity, and energy capacity are 7.74 MW min −1 , 7.88 MW, and 1829.38 MJ, respectively, and these parameter values are greater than condensate water flowrate directly increases or decreases 60%, which means condensate throttling coupling with thermal storage tanks can improve operational flexibility performances. The work is expected to reveal the performance parameters and strategies to provide detailed guidance of using turbine energy storage to improve operational flexibility of the coal-fired power plants.

In order to improve solid particle erosion (SPE) resistance for steam turbine blades and nozzles, in corporation with Kobe Steel, Ltd., evaluation of hard coatings of TiN and TiAlN deposited by the Arc Ion Plating (AIP ® ) process was performed to verify applicability to an actual steam turbine. The results of high-temperature steam oxidation tests and room-temperature sand erosion tests showed that the TiAlN coating had high-temperature stability superior to that of the TiN coating, and erosion resistance far superior to that in the case of the conventional CrC thermal spray coating and boronizing treatment. High-temperature fatigue and creep tests showed that the characteristic strength of the blade material with the TiAlN coating was equal or superior to that of the base blade material. On the basis of the results of comprehensive evaluation, it was confirmed that the TiAlN hard coating has excellent applicability to an actual steam turbine and it was successfully applied to steam turbine blades of power plants in Japan.

Low frequency oscillation is one of the most important factors that restrict the tie-line power flow of network. Its effective suppression is necessary to ensure safety and stability of the power system. The conventional power system stabilizer (PSS) is still insufficient in suppressing consider the frequency range and types of oscillation, so it is necessary to study the auxiliary suppression of the oscillation from the turbine side by using the electro-mechanical coupling theory. In this paper, a governorside power system stabilizer (GPSS) based on active power signal is designed, and its working principle, system structure and parameter setting method are introduced, the effective response frequency boundary of oscillation is also analyzed. Theoretical analysis and simulation results show that this GPSS can suppress in the whole frequency range of low frequency oscillation, and it is suitable as an auxiliary means of low frequency oscillation suppression. (CSPE)

This paper presents a novel method of integrating Phase Change Materials (PCMs) and Silicone oil within the Evacuated solar Tube Collectors (ETCs) for application in Solar Water Heaters (SWHs). In this method, heat pipe is immersed inside the phase change material, where heat is effectively accumulated and stored for an extended period of time due to thermal insulation of evacuated tubes. The proposed solar collector utilizes two distinct phase change materials (dual-PCM), namely Tritriacontane paraffin and Erythritol, with melting temperature 72 °C and 118 °C respectively. The integration of Silicone oil for uniform melting of the PCMs, utilizes the convective heat transfer inside the evacuated tubes, as this liquid polymerized material is well known for its temperature-stability and an excellent heat transfer medium. The operation of solar water heater with the proposed solar collector is investigated during both normal and stagnation (on-demand) operation. The feasibility of this technology is tested via small scale and large scale commercial solar water heaters. Beyond the improved functionality for solar water heater systems, the results from this study show show efficiency improvement of 26% for the normal operation and 66% for the stagnation mode compared with standard solar water heaters that lack phase change materials and silicone oil. The benefit of this method includes improved functionality by delayed release of heat, thus providing hot water during the hours of high demand or when solar intensity is insufficient such in a cloudy day and during night time.

Fast valving of ultra-supercritical unit has great effects on over-speed prevention, load-shedding control, transient stability analysis of electrical system and other security problems. The purpose of fast valving is to maintain the stability of power system once fault or load shedding of unit occurs in the electric power system. Therefore, it is of great significance to study the reliability of fast valving for ultra-supercritical unit. In this paper, the KU ( short shedding) logic condition of SIEMENS T3000 system is analyzed as the research object of fast valving. The unit can be avoided over speed by monitoring the unit load and fast valving under faulty grid conditions based on the KU control. A series of measures will be taken after KU is triggered, for instance the governing valving will be closed quickly and the DEH (digital electro-hydraulic) control of the steam turbine will be switched to speeding control mode. On the other hand, the unit will return to normal operation if the transient fault of power grid disappears. The key contributions of this thesis include three parts: Firstly, based on the analysis of control characteristics of ultra-supercritical unit and protective logic and triggered conditions of KU function, a novel dynamic model by coupling the fast valving of steam turbine and the transient stability of generator is established by applying the PSCAD software. Then, the dynamic response process of ultra-supercritical unit is simulated and calculated by adopting the coupling dynamic model when KU function is triggered. Also the influence factors and reliability of fast valving are analyzed under transient fault conditions. Finally, two optimized measures by increasing the time delay and the speed of quantitative judgment are put forward to reduce risks and avoid the misoperation of signal distortion which may be caused by the power transmitter under transient fault conditions. The results of this study can not only help to evaluate the reliability of fast valving function scientifically in power grid transient fault, but also guide the technicians to analyze the stability of the power grid.

Coal is a valuable primary energy source that has excellent supply stability and economic efficiency. Japan has extremely low energy self-sufficiency and coal-fired power generation is positioned as an important base load power supply. One urgent issue we face is to find realistic countermeasures that greatly reduce CO 2 emissions from coal-fired power plants which produce a large volume of CO 2 emissions. Therefore, we have launched the Osaki CoolGen Project since April 2012 as an “Integrated Coal Gasification Fuel Cell Combined Cycle (IGFC) Demonstration Project” subsidized by the Ministry of Economy, Trade and Industry (until 2015 FY) and New Energy and Industrial Technology Development Organization (from 2016 FY). This project aims to realize innovative low-carbon coal-fired power generation that combines an IGFC, an extremely efficient coal-fired power generation technology with high-performance CO 2 capture technology for the purpose of dramatically reducing CO 2 emissions from coal-fired power generation. This project consists of three steps. The first step will implement demonstration tests of the oxygen-blown Integrated coal Gasification Combined Cycle (IGCC) which is the base technology for IGFC. Toward the start of demonstration testing in March 2017, construction was started in March 2013 and commissioning was started in April 2016. In the second step, we plan to carry out demonstration tests of the oxygen-blown IGCC with CO 2 capture equipment. In the third step, we plan to demonstrate an IGFC system combining the demonstration plant of the second step with a fuel cell.

Swirl stabilized premixed flames are common in industrial gas turbines. The flame shape in the combustor is highly related to the combustion stability and the performance of the gas turbine. In the current paper, the effects of confinement on the time averaged flame structures or flame macrostructures are studied experimentally. Experiments are carried out with swirl number S = 0.66 in two cylindrical confinements with diameters of d 1 = 39 mm and d 2 = 64 mm and confinement ratio c 1 = 0.148 and c 2 = 0.0567. All the experiments were carried out in atmospheric. CH ∗ chemiluminescence from the flame was recorded to visualize the flame behavior. An inverse Abel image reconstruction method was employed to better distinguish the flame macrostructures. Different mechanisms forming the time averaged M shape flames are proposed and analyzed. It is found that the confinement wall plays an important role in determining the flame macrostructures. The flow structures including the inner and outer recirculation zones formed in the confinement are revealed to be the main reasons that affects different flame macrostructures. Meanwhile, the alternation of flame shapes determines the flame stability characteristics. A smaller confinement diameter forced the flame front to bend upstream into the outer recirculation zone hence forming a M shape flame. A strong noise caused by the interaction of the flame front in the outer recirculation zone with the combustor wall was observed. Another unsteady behavior of the flame in the bigger combustor, which was caused by the alternation of the flame root position inside and outside the premixing tube, is also presented. The V shape flame in the two combustors radiated weaker chemiluminescence but the main heat release zone was elongated than the M shape flame. Other operating conditions, i.e. total mass flow rate of the air flow and the equivalence ratio also affect the flame macrostructures. The flame blowout limits were also altered under different test conditions. The bigger confinement has better performance in stabilizing the flame by having lower lean blowout limits.

Colorless Distributed Combustion (CDC) has been shown to provide unique benefits on ultra-low pollutants emission, enhanced combustion stability, and thermal field uniformity. To achieve CDC conditions, fuel-air mixture must be properly prepared and mixed with hot reactive gases from within the combustor prior to the mixture ignition. The hot reactive gases reduce the oxygen concentration in the mixture while increasing its temperature, resulting in a reaction zone that is distributed across the reactor volume, with lower reaction rate to result in the same fuel consumption. The conditions to achieve distributed combustion were previously studied using methane and other fuels with focus on pollutants emission and thermal field uniformity. In this paper, the impact of distributed combustion on noise reduction and increased stability is investigated. Such reduced noise is critical in mitigating the coupling between flame and heat release perturbations and acoustic signal to enhance the overall flame stability and reduce the propensity of flame instabilities which can cause equipment failure. Nitrogen-carbon dioxide mixture is used to simulate the reactive entrained gases from with the combustor. Increasing the amounts of nitrogen and carbon dioxide reduced the oxygen concentration within the oxidizing mixture, fostering distributed combustion. Upon achieving distributed combustion, the overall flame noise signature decreased from 80 dB to only 63 dB, as the flame transitioned from traditional swirl flame to distributed combustion. The flow noise under these conditions was 54 dB, indicating that distributed combustion has only 9 dB increase over isothermal case as compared to 26 dB for standard swirl flame. In addition, the dominant flame frequency around 490Hz disappeared under distributed combustion. For the traditional swirl flame, both the acoustic signal and heat release fluctuations (detected through CH ∗ chemiluminescence) had a peak around 150Hz, indicating coupling between the heat release fluctuations and pressure variation. However, upon transitioning to distributed combustion, this common peak disappeared, outlining the enhanced stability of distributed combustion as there is no feedback between the heat release fluctuations and the recorded acoustic signal.

Access to electricity is a key necessity in today’s World for economic growth and improvements in quality of life. However, the global challenge is addressing the so-called Energy Trilemma: how to provide secure, affordable electricity while minimizing the impact of power generation on the environment. The rapid growth in power generation from intermittent renewable sources, such as wind and photovoltaics, to address the environmental aspect has created additional challenges to meet the security of supply and affordable electricity aspects of this trilemma. Fossil fuels play a major role in supporting intermittent renewable power generation, rapidly providing the security of supply needed and ensuring grid stability. Globally diesel or other fuel oils are frequently used as the primary fuel or back-up fuel for fossil-fueled power generation plants at all scales, from a few kiloWatts to hundreds of MegaWatts, and helps provide millions of people with secure electricity supplies. But diesel is a high polluting fuel, emitting high levels of carbon dioxide (CO 2 ) per unit of fuel input compared to natural gas, as well as high levels of combustion contaminants that are potentially hazardous to the local environment and human health. Additionally, diesel can be a high cost fuel in many countries, with imports consuming significant portions of sometimes scarce foreign currency reserves. Most observers consider that natural gas is the ‘fuel of choice’ for fossil power generation due to its reduced CO 2 emissions compared to coal and diesel. However, access to gas supplies cannot be guaranteed even with the increased availability of Liquefied Natural Gas (LNG) and Compressed Natural Gas (CNG). Additionally where natural gas is available, operators may opt for an interruptible gas supply contract which offers a lower tariff than a firm gas supply contract, therefore there is a need for a back-up fuel to ensure continuous power supplies. While traditionally diesel or Heavy Fuel Oil (HFO) has been used as fuel where gas is not available or as a back-up fuel, propane offers a cleaner and potentially lower cost alternative. This paper compares the potential economic, operational and environmental benefits of using propane as a fuel for gas turbine-based power plants or cogeneration plants.

Energy and water are mutually dependent, limited resources that are critical to the development and economic stability of the United States. Energy production requires large volumes of water, and water treatment and distribution requires large amounts of energy. In 2010, water and wastewater treatment accounted for roughly 1.8% of total electricity use in the United States, which corresponded to 69 TWh per year or, in terms of power-generating capacity, over 7.8 GW. Population growth and climate change will result in increased demand on these limited resources, making them not sustainable at present use levels. In recent years, both forward osmosis (FO) and membrane distillation (MD) have garnered significant attention as next-generation water desalination and reuse technologies with the potential to significantly reduce the energy cost associated with wastewater treatment. Critical technical hurdles and lack of operational understanding, however, have limited development of these individual technologies beyond the laboratory scale. In FO, a draw solution that produces high osmotic pressure but is still easily separable is a major challenge limiting the applicability of this process. The use of MD has been limited by membrane flooding due to oily and surfactant like compounds in industrial wastewaters and the transfer of volatile compounds across the membrane. Combining these technologies in a hybrid process overcomes their individual limitations, while exploiting the benefits of each. Effectively the FO unit pretreats the resulting diluted FO draw solution that is sent to the MD for regeneration via low-grade heat and product water recovery. The regenerated (re-concentrated) draw solution is then recycled to the FO unit. A key advantage of MD is that it is not limited by feed-solution osmotic backpressure, making it ideal for regenerating high-osmotic-pressure FO draw solutions. This, in turn, leads to strong potential for the integrated FO/MD process to treat high-salinity wastewaters that are difficult to treat economically by conventional technologies. The product water leaving the MD unit will be extremely high quality and directly suitable for reuse. With funding from the U.S. Department of Energy, RTI, in collaboration with industrial partner Veolia, has developed an integrated FO/MD process from lab to small pilot scale. In this presentation, pilot-scale testing efforts of this process technology with real industrial wastewater will be presented. Process performance data obtained on full-size FO and MD membrane modules as well as lessons learned from piloting scale-up and best application areas for the technology will be discussed.

To protect against global warming, a massive influx of renewable energy is expected. Although hydrogen is a renewable media, its storage and transportation in large quantity is difficult. Ammonia, however, is a hydrogen energy carrier and carbon-free fuel, and its storage and transportation technology is already established. Although ammonia combustion was studied in the 1960s in the USA, the development of an ammonia combustion gas turbine had been abandoned because combustion efficiency was unacceptably low. Since that time, in the combustion field, ammonia has been thought of as a fuel N additive in the study of NOx formation. Recent demand for hydrogen carrier revives the usage of ammonia combustion, but no one has attempted an actual design setup for ammonia combustion gas turbine power generation. The National Institute of Advanced Industrial Science and Technology (AIST) in Japan successfully performed ammonia-kerosene co-fired gas turbine power generation in 2014, and ammonia-fired gas turbine power generation in 2015. In the facilities, a regenerator-heated, diffusion-combustion micro-gas turbine is used, and its high combustor inlet temperature enables high thermal efficiency of ammonia combustion compared with that of methane combustion. Adoption of the regenerator increased combustor inlet temperature and enhanced flame stability in ammonia-air combustion. Although NOx emission from a gas turbine combustor is high, a Selective Catalytic Reduction (SCR) after gas turbine combustor reduces NOx emission to less than 10 ppm. This means that the ammonia combustion gas turbine design, abandoned in the 1960s for its unacceptably low combustion efficiency, has performed successfully with regenerator and SCR technology. However, the weakness of these facilities was that they required large-size SCR equipment in order to suppress a high concentration of NOx. Although NOx reduction in the combustion process is desirable, low NOx combustion technology is difficult because ammonia had been thought of as a source of fuel-NO. In the case of premixed ammonia-air flame, there exists a low emission window of NOx and NH 3 in a certain equivalence ratio, but combustion intensity is very low because the laminar burning velocity of NH 3 -air is one-fifth that of CH 4 -air. This means that, when utilizing the window of premixed ammonia-air flame, scale-up of the combustion chamber or fuel additives for enhancement of flame stability is necessary. This study shows that the addition of H 2 is effective for low NOx combustion with high combustion efficiency. In addition, H 2 can be easily made from NH 3 decomposition. The other option is diffusion combustion. Further research on low NOx combustion is needed.

Clean gas turbine combustion research has gained popularity in power generation and propulsion industry in recent days. Present days, advanced efficient emission (NOx, CO and UHC) reduction combustion technologies are acknowledged for using the lean premixed combustion system. To support continuous development of eco-friendly combustion system, a 4 th generation dry low NOx prototype downscaled burner (designed and manufactured by Siemens Industrial Turbomachinery AB) has been researched experimentally and numerically. The research burner has multiple stages, which includes a central Pilot (named as RPL/Rich-Premixed Lean) stages, Pilot stage and Main stage. The RPL combustion chamber holds the primary flame, which produces the temperature and high concentration of radicals. The radicals and hot product is reached to the forward stagnation point of the Main flame anchoring point. Swirled reactant mixture is delivered to the Main combustion zone and a strong recirculation zone is developed. The recirculated product is moved to the Main flame root and ignites the fresh mixture. The Main flame was visualized by applying Chemiluminescence and 2D OH-PLIF imaging techniques. Emission measurement was performed to quantify the burner operability and emission competency. Burner stage fuel splits are varied and their effects on flame stability was monitored thoroughly. Computational fluid dynamic (CFD) analysis was performed to understand the flow field and compare the experimental results with numerical analysis. CFD simulation can help to identify the approximate NOx formation region and flame locations inside the burner. RPL flow and Pilot fuel split shows significant contribution towards flame stabilization as experienced from experiment and CFD. A high temperature B-type thermocouple was positioned at the liner exit to measure the exhaust gas temperature. Numerical calculation prediction and measured temperatures showed good qualitative agreement. From the present experimental and numerical research, it is evident that the downscaled prototype gas turbine burner demonstrates a wide flame stability for various operating condition. The fundamental physics behind the flame stabilization and flame dynamics were explored using numerical and experimental research.

Colorless Distributed Combustion (CDC) has been shown to provide singular benefits on ultra-low pollutants emission, enhanced stability and thermal field uniformity. To achieve CDC conditions, fuel-air mixture must be properly prepared and mixed with hot reactive gases from within the combustor prior to the mixture ignition. Hot reactive gases reduce the oxygen concentration in the mixture while increasing its temperature. In this paper, the impact of fuel type (methane, propane, and hydrogen enriched methane) on achieving distributed combustion is investigated. A mixture of nitrogen and carbon dioxide was mixed to simulate the hot recirculated gases at different temperatures using normal air upstream of the combustor. Increasing the amounts of nitrogen and carbon dioxide reduced the oxygen concentration within the combustor. Distributed combustion was identified through OH* chemiluminescence distribution across the combustor. For methane, this oxygen concentration varied between 13.8% and 11.2% (depending on the mixture temperature) with some 85% reduction in NO emissions as compared to that without entrainment. Similar behavior was demonstrated with propane and hydrogen enriched methane, albeit at a lower oxygen concentration (13.7%–11.6% and 12.2%–10.5%), to result in 94% and 92% reduction in NO emission, respectively. The inlet gas temperature was varied between 300K and 750K. Experimental data using a variety of fuels showed NO emissions of 1 PPM or less. Analysis and extrapolation of obtained data suggest that distributed combustion can be achieved at an oxygen concentration of 9.5% for hot reactive entrained gases having a temperature of 1800K. This value may be used as a guideline to achieve distributed combustion with ultra-low emission.

Dye Sensitized Solar Cells (DSSCs) are low cost solar cells offering big room for improvements in its photovoltaic performance by maneuvering semiconductor properties, dye adsorption, electrolyte stability etc. For the first time, we have co-doped TiO 2 with silver (Ag) and copper (Cu) to enhance both charge collection and light absorption as well as reduce recombinations for DSSCs. For high solar cell efficiency 3wt% Cu and 3wt% Cu:Ag doped TiO 2 nps were successfully prepared for Dye Sensitized Solar Cells (DSSCs). Modified photoanode was prepared using surface adsorbed N719 dye on doctor blade coated TiO 2 , Cu:TiO 2 and Cu:Ag:TiO 2 thin films. It was observed that optimum doping concentration of Cu and silver was 3wt% each. DSSCs with Cu:Ag:TiO 2 thin film showed higher conversion efficiency under full sunlight illumination when compared to DSSCs assembled using Cu:TiO 2 and undoped TiO 2 . The obtained efficiencies for DSSCs with undoped TiO 2 , Cu:TiO 2 and Cu:Ag:TiO 2 photoanodes were 2%, 2.7% and 4.5% respectively. Solar cells assembled with Cu only doped TiO 2 electrode when compared with cells assembled using pristine TiO 2 , showed an increase in Voc while Jsc was decreased Furthermore, cells doped with both Ag and Cu showed enhancement in both V oc and J sc . The enhancement in cell performance has been discussed in context of morphology, crystal phase, presence of bonds etc. in nanoparticles. Considering overall better performance, Cu:Ag doped TiO 2 photoanodes can be considered as potential photoanodes in DSSCs.

The refractory belt installed in primary combustion zone provides simplest and most effective solution to suppress ignition delay and enhance combustion stability for low volatile anthracite and lean coal. The fouling deposition generally formed on radiative refractory lined wall of the boiler due to a high surface temperature. The growth of deposition thickness is mainly dependent on the parcile impact on the surface of water wall. A particle capture submodel was used to determine whether a particle was captured to form deposition or not when it reached the furnace wall, and the particle capture criterion was based on the particle’s viscosity and the temperature of the furnace wall. A reduced fouling deposition model was implemented in a three dimensional simulation of a tangentially fired boiler. The numerical investigation was conducted to assess the performance of different layouts of refractory belt. Furnace temperature, surface temperature of refractory belt, and deposition distributions on the furnace wall should be taken into account when layouts of refractory belt are optimized. Based on this, three layouts of refractory belt were proposed for tangentially fired boilers. A numerical investigation was conducted to assess the performance of different layouts of refractory belt and the results showed that the temperature in furnace was increased, and the ignition and combustion processes were stabilized when refractory belts were installed. The reasonable arrangement of refractory belt could reduce the possibility of fouling deposition in furnace.