Gas Temperature Research Articles

Thermodynamic Study on the Vortex Teeth of Electric Scroll Compressors Based on Gradient Tooth Height

Through the analysis of the adhesion between the tooth head and axial clearance leakage attributed to vortex tooth shape deformation, an innovative tooth shape design concept has been introduced entitled “progressive change tooth high vortex tooth”. This unique design includes a gradual change in tooth height and an elevated vortex tooth profile, using temperature-sensitive materials to enhance the resolution of temperature loading on the vortex disc. By refining the process of resolving the temperature loading on the vortex disc, the mean temperature function of the fluid domain along the wall of the vortex tooth is calculated, and a steady-state temperature distribution model for the solid domain of the vortex tooth is formulated. Subsequently, a finite element model for the high eddy current disc is constructed using Abaqus 2021 finite element software, which facilitates the calculation of stress–strain distribution within the high eddy current disc under both gas pressure and temperature field loads. The results show that, especially under conditions of low speed and low exhaust pressure, the temperature load mainly influences the maximum deformation and stress distribution of the vortex tooth. Specifically, under the influence of heat-solid coupling, the maximum deformation of the progressive change tooth high vortex tooth occurs in close proximity to the central compression cavity, reaching up to 13 microns. These results provide a crucial theoretical basis for the structural design and performance optimization of the compressor.

Advancing hydrogen generation: Kinetic insights and process refinement for sorption-enhanced steam gasification of biomass utilizing waste carbide slag

Sorption enhanced steam gasification of biomass (SESGB) presents a promising approach for producing high-purity H2 with potential for zero or negative carbon emissions. This study investigated the effects of gasification temperature, CaO to carbon in biomass molar ratio [CaO/C], and steam flow on the SESGB process, employing carbide slag (CS) and its modifications, CSSi2 (mass ratio of CS to SiO2 is 98:2) and CSCG5 (mass ratio of CS to coal gangue (CG) is 95:5), as CaO-based sorbents. The investigation included non-isothermal and isothermal gasification experiments and kinetic analyses using corn cob (CC) in a macro-weight thermogravimetric setup, alongside a fixed-bed pyrolysis-gasification system to assess operational parameter effects on gas product. The results suggested that CO2 capture by CaO reduced the mass loss during the main gasification as the [CaO/C] increased. The appropriate temperature for SESGB process should be selected between 550 and 700 °C at atmospheric pressure. The appropriate amount of sorbent or steam could facilitate the gasification reaction, but excessive addition led to adverse effects. Operational parameters influenced the apparent activation energy (Ea) by affecting various gasification reactions. For each test, Ea at the char gasification stage was significantly higher than that at the rapid pyrolysis stage. The addition of CS notably increased H2 concentration and yield, while sharply reducing CO2 levels. H2 concentration initially rose and then fell with greater steam flow, peaking at 76.11 vol% for a steam flow of 1.0 g/min. H2 yield peaked at 298 mL/g biomass with a steam flow of 1.5 g/min, a gasification temperature of 600 °C and a [CaO/C] of 1.0. Increasing gasification temperature remarkably boosted the H2 and CO2 yields. Optimal conditions for the SESGB using CS as a sorbent, determined via response surface methodology (RSM), include a gasification temperature of 666 °C, a [CaO/C] of 1.99, and a steam flow of 0.5 g/min, under which H2 and CO2 yields were 464 and 48 mL/g biomass, respectively. CSSi2 and CSCG5 demonstrated excellent cyclic H2 production stability, maintaining H2 yields around 440 mL/g biomass and low CO2 yields (∼60 mL/g biomass) across five cycles. The study results offer new insights for the high-value utilization of agroforestry biomass and the reduction and resource utilization of industrial waste.

Performance Analysis of a New Cogeneration System with Efficient Utilization of Waste Heat Resources and Energy Conversion Capabilities

This paper proposes a new type of cogeneration system coupled by Organic Rankine Cycle (ORC), Absorption Heat Pump (AHP), and Compression Heat Pump (CHP). The new system can meet the needs of different scenarios. Simulations were conducted to analyze the effect of different factors on the parameters and performance indexes of the new system and compared with the system of ORC, AHP, CHP. The results showed that the factors of flue gas temperature at evaporator1 outlet and CHP have the greatest effect on the parameters and performance indexes of the Organic Absorption-Compression Coupling Heat Power (OACCHP) system, and the effect of AHP on the parameters and performance indexes of the OACCHP system can be ignored. In the given range of flue gas temperature at evaporator1 outlet, the heat production of total and net work is reduced by 1.17% and 33.33%, respectively. In a given range of CHP evaporation temperature, the heat production of the total is reduced by 5.74%. In the given range of the outlet temperature of the gas cooler, the heat production of the total is increased by 10.58%. In a given working condition, compared with the single ORC system, the single CHP system, and the single AHP system, the thermal efficiency, COP, and energy earning rate of the OACCHP system are increased by up to 755.49%, 59.8%, 5.8%, respectively. Finally, the optimal operating conditions for different scenarios were determined.

Following fuel conversion during biomass gasification using tunable diode laser absorption spectroscopy diagnostics

The efficiency of the gasification process and product quality largely depend on the degree of fuel conversion. We present the real-time in-situ tunable diode laser measurements of main carbon and oxygen-containing species in the hot reactor core of a pilot-scale entrained flow biomass gasifier (EFG). The concentrations of CO, CO2, CH4, C2H2, H2O, soot, and gas temperature were measured during the air and oxygen-enriched gasification of stem wood at varying equivalence ratios. The experiments were made at the upper and lower optical ports inside a 4 m long, ceramic-lined, atmospheric EFG, allowing to access the degree of the fuel conversion inside the reactor. The exhaust composition was measured by micro-GC, FTIR, and low-pressure impactor. There was a good agreement between the data measured inside the reactor and at the exhaust for oxygen-enriched gasification implying that the chemical reactions are practically frozen downstream the optical ports. For air, the data indicated that the gasification reactions are still active at the measurement locations. Significant concentrations of C2H2, up to 5000 ppm, were found inside the reactor.

Numerical Study of Porous Cylindrical Containment for the Fuel Element of a Centrifugal Nuclear Thermal Rocket

For deep-space propulsion and interplanetary exploration, the centrifugal nuclear thermal rocket (CNTR) has the ability to achieve a very high specific impulse (Isp) metric beyond that of conventional chemical rockets or solid-core nuclear thermal propulsion systems. The high Isp allows the rocket to use less propellant or achieve a higher velocity for shorter transit times. However, the cylindrical containment structure of a CNTR fuel element encounters extreme conditions, as it houses molten uranium at temperatures exceeding 1408 K, leading to challenges such as dissolution, chemical reactions, and thermal stresses that conventional materials struggle to withstand. This study aims to address this issue by analyzing appropriate materials for constructing the cylindrical containment component. The operating conditions of the annular porous medium that confines the liquid uranium in the centrifugal fuel element are simulated by conducting a comprehensive one-dimensional numerical analysis using a range of candidate porous materials, including Mo, W, zirconium carbide, and silicon carbide. The porous structure facilitates the flow of the hydrogen propellant into the internal molten uranium section, where it gains significant thermal energy while simultaneously cooling the cylinder. The containment cylinder has an internal temperature of 1478.1 K, exceeding the melting point of uranium, while the external gas temperature of the hydrogen propellant is much lower. This temperature difference induces significant thermal stresses in the cylinder. The porous containment cylinder made from molybdenum was able to maintain elastic deformation throughout the thickness of the cylinder, showcasing its ability to handle these extreme thermal stress conditions. Tungsten, on the other hand, experienced plastic deformation at the cylinder’s edges and elastic deformation through the middle radial locations. In contrast, the stresses experienced by the ceramic materials far exceeded their failure stress values, leading to brittle failure. These findings will help with the refinement of the CNTR design, edging it closer to practical implementation.

Long term relationships of electron density with solar activity

Greenhouse gases such as carbon dioxide and methane that are causing climate change may cause long term trends in the thermosphere and ionosphere. The paper aims to contribute to explore long term effects in the ionosphere focusing on the impact of solar activity changes. Peak electron density data derived from vertical sounding measurements covering 65 years at the ionosonde stations Juliusruh (JR055), Boulder (BC840) and Kokubunji (TO536), have been utilized to estimate the long-term behavior of daytime ionospheric F2 layer ionization in relation to the solar 10.7 cm radio flux index F10.7. In parallel, Global Navigation Satellite System (GNSS) based vertical total electron content (TEC) data over the ionosonde stations in combination with the peak electron density data have been used to derive the equivalent slab thickness τ for estimating long-term behavior in the time period 1996-2022. A new approach has been developed for deriving production and loss term proxies for studying long-term ionization effects from F2 layer peak electron density and TEC data. The derived coefficients allow estimating the long-term variation of atomic oxygen and molecular nitrogen concentrations including their ratio during winter months. The noon-time slab thickness values over Juliusruh correlate well with the decrease of F10.7 and the F2 layer peak height and enable estimating the neutral gas temperature. The equivalent slab thickness decreases by about 20 km per decade in the period 1996-2022, indicating a thermospheric cooling by about 100 K per decade for Juliusruh. Whereas the oxygen concentration decreases, the loss term, considered as a proxy for molecular components of the neutral gas, in particular N2, increases with the long-term solar activity variation. Considering 11 years averages of the production and loss terms under wintertime conditions, the long-term study reveals for the O/N2 ratio a percentage decrease of 5% per decade and for F10.7 about 3.1% per decade in a linear approach referred to the year 1970. Linear models of 11 years averaged NmF2 and foF2 from corresponding F10.7 show a very close correlation with the temporal variation of F10.7 until about 1990. The root mean square errors are in the order of 1.0 -1.3 ‧1010m-3 for NmF2 and 0.03-0.05 MHz for foF2. After 1990 the linear models clearly deviate from F10.7 at all selected ionosonde stations indicating a non-local effect.

The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE. III. The large scale distribution of DCO+, DNC, and DCN in the DR21 filament

Deuterated molecules and their molecular D/H-ratios ($R_D$(D)) are important diagnostic tools with which to study the physical conditions of star-forming regions. The degree of deuteration, $R_D$(D), can be significantly enhanced over the elemental D/H-ratio depending on physical parameters such as temperature, density, and the ionization fraction. Within the Cygnus Allscale Survey of Chemistry and Dynamical Environments (CASCADE), we aim to explore the large-scale distribution of deuterated molecules in the nearby ($d 1.5$ kpc) Cygnus-X region, a giant molecular cloud complex that hosts multiple sites of high-mass star formation. We focus on the analysis of large-scale structures of deuterated molecules in the filamentary region hosting the prominent region DR21 and DR21(OH), a molecular hot core that is in an earlier evolutionary state. The DR21 filament has been imaged using the IRAM 30-m telescope in a variety of deuterated molecules and transitions. Here we discuss the HCO+ HNC, and HCN molecules and their deuterated isotopologs DCO+ DNC, and DCN, and their observed line emissions at 3.6, 2, and 1.3 mm. The spatial distributions of integrated line emissions from DCO+ DNC, and DCN reveal morphological differences. Notably DCO+ displays the most extended emission, characterized by several prominent peaks. Likewise, DNC exhibits multiple peaks, although its emission appears less extended compared to DCO+ . In contrast to the extended emission of DCO+ and DNC, DCN appears the least extended, with distinct peaks. Focusing only on the regions where all three molecules are observed, the mean deuteration ratios for each species, $R_D$, are 0.01 for both DNC and DCN, and $=0.005$ for DCO+ respectively. Anticorrelations are found with deuterated molecules and dust temperature or $N$( H2 The strongest anticorrelation is found with $R_D$( DCO+ ) and $N$( H2 ), with a Pearson correlation coefficient of $ -0.74$. We analyzed the SiO emission as a tracer for shocks and the $N$(HCO)/$N$( H^13CO+ ) as a tracer for increased photodissociation by ultraviolet radiation. It is suggested that the anticorrelation of $R_D$( DCO+ ) and $N$( H2 ) is a result of a combination of an increased photodissociation degree and shocks. A strong positive correlation between the ratio of integrated intensities of DCN and DNC with their 13C-isotopologs is found in high-column-density regions. The positive relationship between the ratios implies that the D-isotopolog of the isomers could potentially serve as a tracer for the kinetic gas temperature.

Evaluation of ethanol-gasoline blends in SI engines using experimental and ANN techniques

Abstract Fuel combustion has become a major global concern, with much research focusing on the various emissions resulting from different types of fuels. Due to the harmful pollutant emissions from fossil fuels, the world has turned to renewable and alternative fuels to limit toxic emissions and greenhouse effects. Ethanol is a biofuel that, when used in spark ignition engine with gasoline can improve the octane number, combustion efficiency, and produce less emissions. The current research studies the effect of different ethanol blends E0, E5, E10, and E15 with gasoline 92 on engine performance parameters and emissions of a GX35 four stroke engine at different engine speeds. The results along the speed range reveal that increasing ethanol amount leads to an average increase of 2.7%, 1%, and 1.1% in brake power (BP), brake thermal efficiency (BTE), and CO2 emissions, respectively. Meanwhile, it causes an average decrease of 28 ℃, 3%, 15 ppm, and 0.18% in exhaust gas temperature (EGT), brake specific fuel consumption (BSFC), HC, and CO emissions respectively. Moreover, the current study develops an Artificial Neural Networks (ANN) model for predicting performance and emissions of spark ignition (SI) engine. Python programming language is used for ANN coding to train and validate the ANN model with E15. Regression plots were generated to visualize the correlation between the target and predicted data, indicating outstanding performance. The results confirmed the model's reliability for BP, EGT, CO, CO2, and HC parameters with R2 value more than 0.99 and with acceptable performance for BSFC and BTE with R2 of 0.9339, and 0.9708, respectively.

Insight in NO synthesis in a gliding arc plasma via gas temperature and density mapping by laser-induced fluorescence

A gliding arc (GA) plasma, operating at atmospheric pressure in a gas mixture of 50% N2 and 50% O2, is studied using laser-induced fluorescence spectroscopy. The main goal is to determine the two-dimensional distribution of both the gas temperature and the NO ground state density in the afterglow. As GA plasma discharges at atmospheric pressure normally produce rather high NO x densities, the high concentration of relevant absorbers, such as NO, may impose essential restrictions for the use of ‘classical’ laser-induced fluorescence methods (dealing with excitation in the bandhead vicinity), as the laser beam would be strongly absorbed along its propagation in the afterglow. Since this was indeed the case for the studied discharge, an approach dealing with laser-based excitation of separate rotational lines is proposed. In this case, due to a non-saturated absorption regime, simultaneous and reliable measurements of both the NO density and the gas temperature (using a reference fitting spectrum) are possible. The proposed method is applied to provide a two-dimensional map for both the NO density and the gas temperature at different plasma conditions. The results show that the input gas flow rate strongly alters the plasma shape, which appears as an elongated column at low input gas flow rate and spreads laterally as the flow rate increases. Finally, based on temperature map analysis, a clear correlation between the gas temperature and NO concentration is found. The proposed method may be interesting for the plasma-chemical analysis of discharges with high molecular production yields, where knowledge of both molecular concentration and gas temperature is required.

Machine learning-driven real-time identification of large-space building fires and forecast of temperature development

In firefighting, real-time knowledge of fire dynamics is crucial yet often unavailable. The building geometry and measured gas temperatures are integrated to ascertain fire states and predict temperature evolution, utilizing a machine learning framework that combines long short-term memory networks and transfer learning. The model is pre-trained on datasets with 1000 samples from parametric fire models and 200 from field simulations, enabling real-time predictions with on-site data. Numerical simulations in portal frame buildings demonstrate over 95 % accuracy in identifying fire states and 90 % in predicting gas temperatures. A method using correlation coefficients and standard deviations effectively detects damaged thermocouples with over 96% accuracy, given a damage ratio below 30 %. Validation in two real fire scenarios showed more than 92 % accuracy in locating fires and over 89 % in forecasting gas temperatures 20 min ahead, which costs 2.14 s and 1.83 s, respectively. The machine learning framework also exhibits robustness to changes in ventilation conditions by making temperature predictions using reliability theory. The proposed framework provides clear information about the state and development of the fire to firefighters and is useful for promoting smart firefighting

Numerical analysis of scroll compressor performance with pre-discharge valve for low-temperature heat pumps

Scroll compressors are a crucial component of automotive air conditioning systems. When operating at off-designed working conditions, over-compression can occur in the scroll compressor. A pre-discharge valve (PDV) is proposed to enhance the performance of the scroll compressor under off-design working conditions. The performance of the scroll compressor with a PDV for a low-temperature heat pump system is simulated. The results show that the scroll compressor with the PDV structure has lower pressure in the compression chambers and improved over-compression compared to conventional scroll compressors. The use of the PDV also leads to a reduction in the temperature of the refrigerant gas in the compression chambers and a decrease in the leakage between the compression chambers. As the evaporating temperature increases from −25 °C to −5 °C, the mass flow rate and volumetric efficiency increase, and the discharge temperature decreases. At an evaporating temperature of −5 °C, the discharge temperature at the center discharge port of the scroll compressor with the PDV is reduced by 2.4 °C compared to the conventional scroll compressor. The input power of the scroll compressor is reduced by 165.4 W–897.7 W. The volumetric efficiency and the isentropic efficiency are improved by 0.13 % and 6.63 % respectively.

LAS-on-Edge: A Real-Time Laser Absorption Spectroscopic Water Vapor Sensor on Edge Computing Platforms

Real-time and in situ water vapor (H2O) sensors are increasingly demanded to indicate thermochemical parameters of energy systems. As an accurate, fast and non-intrusive sensing technology, laser absorption spectroscopy (LAS) enables simultaneous measurement of gas concentration and temperature. Due to the complex spectral computation, real-time and rapid LAS signal processing are still challenging. Most state-of-the-art LAS sensors utilize high-level computing units to post-process laser measurements in real time, hindering their portable deployment in harsh industrial environments. To address the above challenge, we developed an online LAS gas sensor on edging computing platforms, named as LAS-on-Edge. The developed sensor achieves an online monitoring rate up to 62.5Hz by deploying a spectral-informed neural network on an embedded device. Simultaneously, it reserves the raw kilo-Hz measurements offline for underlying dynamics understanding. The LAS-on-Edge sensor’s compactness also enables its flexible and in situ integration. The sensor is firstly used to monitor a slow mist diffusion and accumulation process, exhibiting a high measurement accuracy with low spectra recovery residuals below 0.01. It is further applied to online monitor the H2O concentration and temperature variation during a lab-scale propane combustion process. It demonstrates a minimal temperature deviation of 1.86% compared to the thermocouple reference in the flame. The sensor also successfully detects the fundamental flame pulsation at 5.65Hz as well as high-frequency pulsations exceeding 200Hz, thereby effectively reveals underlying flame dynamic behaviors.

Proposal and performance analysis of a novel hydrogen and power cogeneration system with CO2 capture based on coal supercritical water gasification

To establish a sustainable energy system, it is essential to achieve low-carbon and clean utilization of coal. In this study, a novel hydrogen and power cogeneration system with full CO2 capture that based on coal supercritical water gasification (SCWG) is proposed. Hydrogen is separated from syngas produced by coal SCWG, and the remaining combustible gas is burned to generate power. Moreover, supercritical CO2 cycle is integrated within the cogeneration system to recover the waste heat with high exergy efficiency. Thermodynamic performances, effects of key operation parameters and off-design performances under part-load conditions of the cogeneration system are analyzed. Under the design condition, the cogeneration system produces 20.26 mol kg−1 hydrogen and generates 8746 kJ kg−1 net power, achieving the high energy efficiency and exergy efficiency of 54.77% and 52.54%. The exergy efficiency of cogeneration system can be enhanced by optimizing the operation parameters, which is increased by 0.42%, 4.03% and 1.10% with the optimal coal water slurry concentration (17.5%), higher gasification temperature (750°C) and higher gas turbine inlet parameters (1500°C/3 MPa), respectively. The cogeneration system performance decreases with the power load, and the exergy efficiency decreases by 9.61% when the system power load reduces from 100% to 30%.

Thermodynamic and life cycle assessment analysis of polymer-containing oily sludge supercritical water gasification system combined with Organic Rankine Cycle

With the development of polymer flooding technology, polymer-containing oily sludge (PCOS) has become a major pollutant on offshore oil platforms. Supercritical water gasification system is an efficient and pollution-free technology compared to conventional PCOS treatment. However, the system model for PCOS has not yet been established and the theoretical model for system optimization is insufficient. In this work, a novel auto-thermal system is established based on supercritical water gasification technology for the treatment of PCOS. Through the thermodynamic analysis, an optimization plan is concluded and used for the establishment of a modified system with Organic Rankine Cycle. Results show that the two-stage reactor reduces the gasification reaction temperature from 652 °C to 502 °C, and the Organic Rankine Cycle system using Isopropanol recover 9.1 % chemical exergy of feedstock with the optimal parameters (superheat, evaporation temperature and circulating pressure). The energy and exergy efficiency of the modified system has increased by 52.4 % and 42.4 % compared to the original system. Besides, a life cycle assessment is adopted for the environment analysis. The results show that the increasing gasification temperature and PCOS slurry concentration can reduce system unit exergy loss. Global Warming Potential reaching the minimum value of 26.1 at 65 wt%.

PDRs4All

Context. Mid-infrared emission features are important probes of the properties of ionized gas and hot or warm molecular gas, which are difficult to probe at other wavelengths. The Orion Bar photodissociation region (PDR) is a bright, nearby, and frequently studied target containing large amounts of gas under these conditions. Under the “PDRs4All” Early Release Science Program for JWST, a part of the Orion Bar was observed with MIRI integral field unit (IFU) spectroscopy, and these high-sensitivity IR spectroscopic images of very high angular resolution (0.2″) provide a rich observational inventory of the mid-infrared (MIR) emission lines, while resolving the H II region, the ionization front, and multiple dissociation fronts. Aims. We list, identify, and measure the most prominent gas emission lines in the Orion Bar using the new MIRI IFU data. An initial analysis summarizes the physical conditions of the gas and demonstrates the potential of these new data and future IFU observations with JWST. Methods. The MIRI IFU mosaic spatially resolves the substructure of the PDR, its footprint cutting perpendicularly across the ionization front and three dissociation fronts. We performed an up-to-date data reduction, and extracted five spectra that represent the ionized, atomic, and molecular gas layers. We identified the observed lines through a comparison with theoretical line lists derived from atomic data and simulated PDR models. The identified species and transitions are summarized in the main table of this work, with measurements of the line intensities and central wavelengths. Results. We identified around 100 lines and report an additional 18 lines that remain unidentified. The majority consists of H I recombination lines arising from the ionized gas layer bordering the PDR. The H I line ratios are well matched by emissivity coefficients from H recombination theory, but deviate by up to 10% because of contamination by He I lines. We report the observed emission lines of various ionization stages of Ne, P, S, Cl, Ar, Fe, and Ni. We show how the Ne III/Ne II, S IV/S III, and Ar III/Ar II ratios trace the conditions in the ionized layer bordering the PDR, while Fe III/Fe II and Ni III/Ni II exhibit a different behavior, as there are significant contributions to Fe II and Ni II from the neutral PDR gas. We observe the pure-rotational H2 lines in the vibrational ground state from 0–0 S(1) to 0–0 S (8), and in the first vibrationally excited state from 1–1 S (5) to 1–1 S(9). We derive H2 excitation diagrams, and for the three observed dissociation fronts, the rotational excitation can be approximated with one thermal (~700 K) component representative of an average gas temperature, and one nonthermal component (~2700 K) probing the effect of UV pumping. We compare these results to an existing model of the Orion Bar PDR, and find that the predicted excitation matches the data qualitatively, while adjustments to the parameters of the PDR model are required to reproduce the intensity of the 0–0 S (6) to S (8) lines.

Particulate removal characteristics of commercial-scale DeNOx catalyst cartridge coupled filter bags

The commercial-scale DeNOx catalyst cartridge coupled with filter bag have been developed for the removal of fine particulate matter and nitrogen oxides (NOx) in flue gases. The DeNOx catalyst cartridge coupled filter bag is made up of a microporous PTFE (polytetrafluoroethylene) membrane/impregnated polyimide fiber needle-punched pleated filter bag designed for the removal of ultrafine particulates, along with a pellet selective catalytic reduction catalyst-filled cartridge for the removal of NOx. V2O5-MoO3/TiO2 catalyst was used as the DeNOx catalyst. The distribution of cleaning air velocity inside the DeNOx catalyst cartridge-coupled filter bag, which is injected with compressed air from the high-volume low-pressure (HVLP) pulse injector to remove the deposited dust cake from the surface of the filter bags during pulse-jet cleaning, was confirmed using computational fluid dynamics (CFD). The particulate removal and dust cake dislodgement characteristics of the DeNOx catalyst cartridge coupled filter bag were tested in a commercial-scale filter bag test unit under conditions simulating fossil fuel combustion flue gas. The commercial-scale DeNOx catalyst cartridge coupled filter bag was 165 mm in diameter, 2000 mm in total length, and contained approximately 12 kg of DeNOx catalyst- filled cartridges. Nine commercial-scale DeNOx catalyst cartridge coupled filter bags were installed in the commercial-scale filter test unit. The experimental conditions were as follows: flue gas temperature 200 °C, flue gas flow rate 3000Nm3/h, NO, SO2, and particulate concentration in inflow flue gas 200 ppm, 7 ppm, and 5000 mg/Nm3 respectively, resulting in different values of filtration velocities. The efficiency of bag cleaning and intervals, overall collection efficiency, fractional efficiency, and filter quality were investigated. The average bag cleaning efficiency and overall collection efficiency were 95.5%, 91.5%, and 83.3% at filtration velocities of 0.8, 1.0 and 1.2 m/min, respectively. The corresponding values for overall collection efficiency were 99.9%, 99.5%, and 98.2%. So, both bag cleaning efficiency and overall collection efficiency decreased with increased filtration velocity. The present study confirmed that DeNOx catalyst cartridge coupled filter bags have relatively higher bag cleaning efficiency, collection efficiency, and filter quality for challenging fossil fuel combustion flue gas. Particularly, the fractional efficiency for micron-sized particles was considerably higher at lower filtration velocities.

Optimization of exhaust ejector with lobed nozzle for marine gas turbine

To attain high-performance ejector configurations, an ejection characteristic testing system was established initially to validate the reliability of the Realizable k-ε turbulent model. Subsequently, optimization investigations were conducted on lobed nozzle ejectors with various structural parameters. The effects of four key structural parameters, including lobed nozzle expansion angle α, lobed nozzle width d, number of lobes in the nozzle n, and height of the square-to-circle section h, were systematically studied. Furthermore, the CRITIC method was employed for multi-objective evaluation to identify the optimal design configuration for the casing ejector. The research findings revealed that among the structural parameters, the lobed nozzle expansion angle α exerted the greatest influence on the ejection coefficient and pressure loss coefficient. The weights of the evaluation criteria were determined by the CRITIC method as follows: ejection coefficient (49.38%) < pressure loss coefficient (50.62%). The optimal design configuration determined by the CRITIC method included α = 45°, d = 150 mm, n = 14, and h = 600 mm. The resulting enclosure design ensures smooth airflow within the system, preventing the backflow of high-temperature mainstream fluid and heating the enclosure. It also maintains a temperature distribution in the typical cross-section that meets specified requirements. Additionally, it facilitates improved mixing of mainstream and secondary fluid and reduces exhaust gas temperature.

Experimental analysis and modeling of gas turbine engine performance: Design point and off-design insights through system of equations solutions

In this article, a systematic approach is presented for simulating turbojet engine performance at both design and off-design points. The construction of gas turbine engines involves a core, with additional components added based on the proposed methodology. Accurate formulation of component characteristics and their matching forms the basis for the system of equations needed for solving off-design engine performance. The developed algorithm's initial step involves comparing results with experimental data obtained from 230 N engines. Experimental testing utilizes a 780 N engine under diverse operating conditions, allowing determination of thrust values, fuel consumption, and outlet gas temperatures. An engine characteristic curve is derived under static conditions at ground level and validated against ground test results in Tehran. Unknown parameters are calibrated using a dedicated model, enabling the extraction of engine performance parameters across different corrected speeds. These results are then compared with GasTurb outputs. Comparative analysis between the proposed model's simulation and experimental data demonstrates high accuracy, affirming the reliability of the presented model.

Research on IoT Based Industrial Monitoring and Protection System

Abstract: ESP32 microcontroller integration is used in an Internet of Things system created for industrial monitoring and security.The device has multiple sensors built in system to collect critical environmental and operating data, such as voltage, current, fire, MQ2 gas, and DHT11 temperature and humidity sensors. For remote monitoring and analysis, an IoT platform hosted in the cloudcan process and transmit data more easily thanks to the ESP32 microcontroller. Industrial parameters can be managed and visualizedin real time using the Blynk application as an interface. A DC fan, pump motor, buzzer, LCD display, and AC device control are examples of output actuators included in the system. Through using these actuators, industrial environments can be made safer and more efficiently run by enabling automated responses to recognized anomalies or predefined thresholds

Cryogenic carbon capture design through [formula omitted] anti-sublimation for a gas turbine exhaust: Environmental, economic, energy, and exergy analysis

To achieve a net zero-emission society, current industries must transition to become less carbon-intensive while fulfilling the rising power demand. In this study, we present a novel multigeneration system that produces power, cooling, and solid carbon dioxide by applying cryogenic carbon capture to a gas turbine flue gas. The energy recovery concept is efficiently employed to avoid energy and exergy losses in the system. The system is simulated in Aspen Plus with the mathematical models of the exergy streams and solid-vapor equilibrium written in Matlab. The performance of the plant is assessed based on energy, exergy, economic, and environmental evaluations. Thermodynamic analysis indicates that 1.2 MJ of electricity is required to capture 1 kg of CO2 from the gas turbine exhaust gas (which is lower compared to conventional systems) with 100 % CO2 purity. The net generated power, energy efficiency, exergy efficiency, m˙CO2,captured, and m˙CO2,emitted for the proposed system are 179.4 MW, 41.2 %, 59.3 %, 500,000 tons annually, and 255,000 tons a year, respectively. Sensitivity analysis shows that reducing the flue gas temperature positively impacts the CO2 content in the flue gas while having a negative effect on energy and exergy efficiency. The economic investigation shows that the system is economically profitable.