Chamber Temperature Research Articles

Numerical simulation of fluid–structure interaction for solid rocket engine nozzle ablation

When a solid rocket engine is ignited, the throat lining of the nozzle is prone to chemical ablation owing to high-temperature gas erosion, resulting in thrust loss. In this paper, a coupled fluid–solid model for thermochemical ablation on the nozzle wall is established based on the multi-component Navier–Stokes equations, SST k-ω turbulence model, finite-rate chemical reaction model on the nozzle wall, variable transport properties of the nozzle material, and the heat conduction equation. Compared with the experimental data, the maximum error of the calculated ablation rate was 4.37%, validating the effectiveness of the model. Subsequently, the effects of different combustion chamber components, pressures, and temperatures on the ablation rate of the carbon–carbon (C/C) throat lining were studied. The results indicate that the temperature at the nozzle throat was the highest, resulting in the maximum ablation rate. As the Al mass fraction at the nozzle inlet increased, the thermochemical ablation rate of the nozzle decreased with a lower oxidizer mass fraction. The inlet pressure and temperature of the nozzle were positively correlated with the ablation rate, with the temperature having a more significant impact than the pressure. These findings provide theoretical guidance for the thermal protection design of rocket engine nozzles.

Reliability tests of the SFP+ transceivers and the TGC readout board for the ATLAS experiment at HL-LHC

Results are presented for reliability tests of the SFP+ transceivers and the readout board of Thin Gap Chambers (TGC) for the ATLAS experiment at HL-LHC. The radiation tolerance was evaluated for the SFP+ transceivers from Broadcom and FS and the TGC frontend board with gamma ray irradiation up to 𝒪(100) Gy at the Cobalt-60 facility of Nagoya University. An accelerated aging test was also performed for the SFP+ transceivers with the Kintex-7 evaluation board integrated in the temperature chamber.

Obtaining heat transfer coefficients (Kv) distribution directly from mass flow measurements during the sublimation step of freeze-drying.

The knowledge of heat transfer coefficients (Kv) and their distribution is a crucial element in the successful transfer of a freeze-drying process to a new piece of equipment. Nevertheless, the implementation of the classical ice sublimation method is resource consuming, particularly in the industrial context, which represents a significant barrier to its application. This paper demonstrates that the Kv distribution can be calculated from the measurement of mass flow during a freeze-drying operation by reversing the results of process simulation calculations. This methodology works independently of the experimental method used to measure the mass flux: tunable diode laser absorption, inlet/outlet temperature difference of the shelves, or chamber/ condenser pressure difference. The advantage of this new method is that it requires no specific experimental effort and can be carried out on routine production runs (especially with the temperature or pressure difference methods), provided the freeze drier possesses at least shelf inlet/outlet temperature measurement and/or chamber and condenser capacitance pressure measurement. Furthermore, the measurement encompasses all vials, which is not achievable using the conventional method for commercial units that contain tens of thousands of vials. Once fed back into the primary drying mechanistic model, the Kv distribution is used to estimate the temperature distribution in the product. In this article, we provide practical examples at all scales, from laboratory to industrial production.

On the optimization of fatigue limit in additively manufactured fiber reinforced polymer composites

Abstract This study uses the Taguchi optimization methodology to optimize the fatigue performance of short carbon fiber-reinforced polyamide samples printed via fused deposition modeling (FDM). The optimal printing properties that maximize the fatigue limit were determined to be 0.075 mm layer thickness, 0.4 mm infill line distance, 50 mm/s printing speed, and 55 °C chamber temperature with layer thickness being the most critical parameter. To qualify fatigue endurance limit, the energy dissipation in uniaxial fatigue was quantified by using hysteresis energy and temperature rise at steady state. From these results, the fatigue limit for a specimen printed with optimized printing parameters was predicted to be 69 and 70 MPa from hysteresis energy and temperature rise at steady state methods, consecutively, and it was experimentally determined to be 67 MPa. This work demonstrates the effectiveness of the Taguchi optimization method when applied to additive manufacturing and the swift ability to predict the fatigue limit of a material with only one specimen to produce optimal additively manufactured components for industrial applications, as validated by experimental fatigue testing.

ИСПОЛЬЗОВАНИЕ ГИДРОЛИЗАТА ДРОЖЖЕВОЙ БИОМАССЫ В ТЕХНОЛОГИИ ЗЕРНОВЫХ ЭКСТРУДАТОВ

The purpose of research is to study the effect of adding yeast biomass hydrolyzate to extruded wheat flour, used as a model base, on the operating parameters of extrusion – temperature and pressure in the extruder chamber, shear moment, which characterizes the energy consumption for the process of processing mixtures, and physicochemical parameters of extruded products. Promising ingredients, sources of protein, essential amino acids and other essential nutrients are yeast biomass and its processed products. A study was conducted on the effect of adding yeast biomass hydrolyzate on the process of extrusion of wallpaper wheat flour and the physicochemical properties of the resulting extrudates. It has been established that extrusion with a fixed productivity of 28 kg/h of mixtures of flour and dried yeast biomass hydrolyzate in an amount of up to 10 % does not significantly affect the extrusion performance parameters; the specific mechanical energy when processing mixtures with yeast biomass hydrolyzate slightly exceeded the specific mechanical energy of flour extrusion. The effect of adding yeast biomass hydrolyzate on the bulk density of extrudates, expansion coefficient, and structural and mechanical properties was insignificant. Analysis of the texture of the samples showed that the addition of yeast biomass hydrolyzate significantly increased the hardness and reduced the number of microfractures in the extrudates obtained by reducing the moisture content and increasing the extruder productivity, which determine the tightening of the extrusion mode. The effect of adding yeast biomass hydrolyzate on the amino acid composition of extrudates was established. It was shown that the content of bound amino acids increased by 14.2 %, free by 412 %. The maximum increase in the content of free amino acids was noted for alanine (18 times), lysine (15.5 times), glutamic acid (13.7 times). For the same acids in a bound state, the increase was 68 %, 49 % and 20.4 %, respectively.

Quantitative measurement of the Sauter mean diameter in dense fuel sprays using simultaneous planar-laser-induced-fluorescence/Mie scattering technique

Abstract The planar laser induced fluorescence (PLIF)/Mie scattering technique has been established as an effective method for measuring the Sauter Mean Diameter (SMD) distribution in dense fuel sprays. This technique typically utilized a 266 nm laser. However, the strong absorption of laser wavelengths ranging from 266 nm to 274 nm in dense fuel sprays affected the detection of Mie scattering signals. Therefore, it was proposed to use a 266 nm laser for fluorescence excitation and a 532 nm laser for Mie scattering radiation in dense fuel sprays. In this study, a look-up table (LUT) was created by correlating the PLIF/Mie ratio with the Sauter Mean Diameter (SMD) using the Phase Doppler Particle Analyzer (PDPA), reducing the SMDerror from 27% to 13%. Furthermore, the proposed method was successfully applied to investigate the atomization field of room temperature and atmospheric pressure in a dual-stage axial swirl combustion chamber. By comparing the time-averaged PLIF images and time-averaged Mie images, the vapor and liquid phases of the fuel in the spray were successfully imaged and identified. The results indicated that, under the same fuel flow, increasing the air mass flow led to a gradual increase in the spray cone angle inside the dual-stage axial swirl combustor. Additionally, at a constant fuel flow, increasing the air mass flow resulted in a more uniform droplet size distribution, thereby enhancing the atomization effect. The presented technique provides a reliable and accurate tool for studying fuel spray behavior under various operating conditions. This knowledge can contribute to the design of more efficient combustion systems and the optimization of fuel injection strategies.

Performance evaluation of indirect solar drying system for potato slices: Comparative analysis with open-sun drying method

Performance evaluation of indirect solar drying system for potato slices: Comparative analysis with open-sun drying method

PEMODELAN MESIN DIESEL DUAL FUEL (DDF) MENGGUNAKAN BAHAN BAKAR BIODIESEL DAN GAS HIDROGEN

Vehicle exhaust emissions are the second largest cause of pollution after industry. Therefore, the government is targeting net zero emissions by 2060. One way to reduce fuel consumption is to use biodiesel. However, the use of biodiesel still has many negative impacts on vehicle performance, namely decreased engine performance. One way to reduce exhaust emissions without reducing engine performance is by adding hydrogen gas. This study was conducted with a simulation to determine the phenomena that occur in the combustion chamber of a single-cylinder diesel engine including hot cylinder pressure, the impact of combustion on exhaust emissions. The stages in this study consist of pre-processing, processing and post-processing. The results of this study indicate that the addition of hydrogen gas can increase the heat in the combustion chamber, the impact of increased heat is an increase in cylinder pressure, combustion chamber temperature, NO emissions, and CO emissions. While HC and soot emissions decreased with the addition of hydrogen gas to biodiesel fuel.

Influence of Different Light-Activated Bleaching Gels on Pulp Chamber Temperature: An In Vitro Study

Background: Significant advances in in-office bleaching treatments have been made by introducing some types of light sources. Halogen lights, LEDs, and diode lasers are the most popular devices used for in-office bleaching. There is a risk that bleaching-activating light sources might increase temperature and have side effects on the dental pulp. This study evaluated the effect of different light-activated bleaching gels on pulp chamber temperature. Methods: In this experimental study, 36 bovine incisor teeth were selected for investigation. The samples were divided into three groups, including Opalescence Xtra Boost PF bleaching gel with the 405 nm LED (group one), Opalescence Xtra Boost PF bleaching gel with 810 nm diode laser (group two), and Heydent bleaching gel with 810 nm diode laser (group three). Bleaching gels with a thickness of 1 mm were applied on teeth surfaces and activated according to the manufacturer’s instructions. The temperature change was recorded every second, and the results of the graph showing the peak temperature were plotted using SPSS software. One-way ANOVA was employed to determine the effect of bleaching type on temperature rise. In case of the presence of a significant difference, post-hoc Tukey’s test was utilized for pairwise comparison of the groups. Results: The temperature rise considerably depends on the light sources. Group one (LED+bleaching gel Xtra boost) had the lowest temperature rise (1.87° C±0.15), while group two (diode laser+bleaching gel Xtra boost) had the highest temperature rise (3.55° C±0.50). There was a statistically noticeable difference in temperature rise among all groups (P<0.05). Conclusion: The light activation of in-office bleaching gels with the diode laser caused higher temperature changes as compared to LED. However, the detected temperature rise was not critical for pulpal health.

INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE TEMPERATURE-TIME MODES OF VACUUM FREEZE-DRYING OF THE PRODUCT

The process of sublimation drying of berries provided, this is the drying method along the berry the humidity is reduced to 2-5%. The dryer is conditional consists of two blocks - refrigeration and sublimation unit. At room temperature the product is placed in the drying chamber. Equipment after connection, vacuum pump in the chamber reduces the pressure to 10-30 Pa. When a vacuum is created and free product due to evaporation of moisture leads to freezing. Most of the moisture is converted into ice crystals, and then the sublimation process begins. This equipment uses 404 a freon. Temperature to register 8 channel OVEN TRM138 RS-485 temperature meter was used. Of the product to measure weight every 30 minutes removed from the chamber Vibra HT 224RCE was weighed on an analytical balance. The experiment was performed with three types of berries: strawberries; currants and raspberries. Experience during the temperatures on the surface of the berries, inside the chamber and the mass of the product were measured. Duration of drying as a criterion of effective mode, energy expenses and quality indicators of dried berries were determined. The effective sublimation time was 4.5 hours. Inside the chamber at a pressure of (20 ± 5) Pa, at a temperature of (-42 ± 2) 0С, general freezing and sublimation time not more than 5 hours, the total drying time is 8 hours. The initial weight of strawberries decreased by 36%, currants by 28% and raspberries by 27.4%. Drying should be stopped when the chamber temperature reaches 40 ° C.

Ground Testing of a Miniature Turbine Jet Engine for Specific Flight Conditions

This paper presents the design and development project of an engine test stand specifically constructed for ground testing of miniature turbine jet engines (MTJEs) along with conclusive results of the conducted investigations. The tested engines serve as the propulsion system for an unmanned aerial vehicle (UAV) platform. The engine test stand was used to determine various operating parameters of the engine, with a particular focus on recording variations and changes in temperature and pressure at the engine control cross-sections: behind the compressor, the combustion chamber, and at the final cross-section of the nozzle. The analysis of the direct test results allowed the evaluation of the engine’s behavior under hydration conditions and documents the quantitative and qualitative response of the control system of the engine. Of particular interest are the results showing an increase in exhaust system temperature with a decrease in the temperature in combustion chamber under hydrated conditions. The test program assumed and considered the acting loads and forces in both standard and specific flight conditions, including scenarios for a heavy rain. The preliminary evaluation of the investigation results provided data and insights required for further analysis. Quantitatively, the measured temperature value in the exhaust system does not exceed 700 °C and the temperature increase resulting from the introduction of water and the engine’s response to the out-of-operation event is approximately 50 °C for the JetCat 140. Qualitatively different effects were observed in the combustion moment, consisting in a drop in temperature values during the introduction of water into the engine flow channel. The introduction of water into the GTM 140 inlet revealed no significant changes in the variations of pressure and temperature measured in selected engine design sections. Based on the knowledge and experience gained, a fully operational test stand to monitor the parameters and performance of the MTJEs, which are used for aerial target propulsion, was developed.

Nesting ecology of Black Caimans, <i>Melanosuchus niger</i> (Spix 1825) (Crocodylia: Alligatoridae), in the Lago doCuniã Extractive Reserve, Amazon, Brazil

The reproductive success of a population is the expression of life history traits such as fecundity andfertility, which are strongly affected by ecological factors. We investigated the use of nesting sites by female BlackCaimans, Melanosuchus niger (Spix 1825) during three consecutive nesting seasons from 2019 to 2021 at Lago doCuniã Extractive Reserve in the southwestern Brazilian Amazon. We examined factors influencing nesting ecologysuch as chamber temperature and applied multiple linear regressions to test hypotheses related to reproductive tradeoffsbetween different variables, such as female, egg, and clutch sizes. We identified trade-offs between egg width,hatchling size, and clutch size, suggesting that larger clutches contain smaller eggs, resulting in smaller hatchlings.A better understanding of crocodilian reproductive strategies and trade-offs are essential to predict the viability ofpopulations and to foster conservation initiatives at the Lago do Cuniã Reserve, where caimans are currently subjectedto a sustainable harvesting management plan.

Research on the Impact of Blending Dissociated Methanol Gas on the Performance and Emissions of Marine Medium-Speed Methanol Engines

This study conducts a detailed analysis of the mixed combustion of dissociated methanol gas (DMG) and methanol in a marine medium-speed methanol engine through numerical simulation methods. The research focuses on the impact of partially replacing methanol with DMG on engine combustion characteristics and emissions under both stoichiometric and lean-burn conditions. Employing the MAN L23/30H diesel engine as the experimental model, direct injection of DMG is achieved by installing gas injectors on the cylinder head. Utilizing the CONVERGE software, we simulate the injection and combustion processes of methanol and DMG and subsequently analyze the effects of varying DMG blending ratios on in-cylinder pressure, heat release rate, mean chamber temperature, as well as NOx, HC, CO, and soot emissions. The research findings indicate that, under stoichiometric combustion conditions at both rated and idle speeds, the incorporation of DMG leads to increases in the peak in-cylinder pressure, peak heat release rate, and peak in-cylinder temperature, with these peaks occurring earlier. Additionally, it is observed that emissions of HC, CO, and soot are reduced. Under lean combustion conditions at rated speed, in the absence of DMG blending, increasing the excess air ratio results in an initial increase followed by a decrease in both fuel-indicated and overall-indicated thermal efficiency. However, with the blending of DMG, these efficiencies improve as the excess air ratio increases. Notably, the highest efficiencies are achieved when the excess air ratio is 1.8 and the blending ratio of DMG is 30%.

Effects of Seed Colour and Regulated Temperature on the Germination of Boswellia pirottae Chiov.: An Endemic Gum- and Resin-Bearing Species.

(1) Background: According to the IUCN, Boswellia pirottae is classified as a vulnerable species. However, knowledge of its seed characteristics and germination behaviour is lacking. (2) Methods: The aim of this research was to characterise the seeds and evaluate the effects of seed colour and controlled temperatures on seed germination. The seeds were segregated into the following colour categories: light brown (LB), brown (B), and dark brown (DB). The seeds were evaluated under controlled constant temperatures (23 °C) and at room (fluctuating) temperature independently. One-way ANOVA, t-test, and germination indexes were used for analyses. (3) Results: The results showed significant differences in the mean seed masses of LB, B, and DB seeds. Similarly, the differently coloured seeds varied in their water imbibition rates. The result showed significant differences in the mean germination of the seeds in both the controlled temperature (23 °C) and room-temperature chambers among the LB, B, and DB seeds. However, the t-test revealed no significant differences in the mean germination of the seeds of similar colours between controlled temperature and room temperature conditions. (4) Conclusions: The seed's colour significantly influenced the seed mass, water imbibition capacity, and germination rate relative to the temperature treatment. Dark brown seeds are recommended for seed collection aimed at seedling propagation.

Simulation of the processes of spraying and combustion of kerosene and liquid oxygen in the chamber of a liquid-propellant rocket engine

The paper presents the results of simulation of spray and combustion processes in the liquid-propellant rocket engine chamber using the z77 reduced kinetic mechanism of chemical reactions and a hybrid method for determining spray parameters of a swirl atomizer. Simulation was carried out for the nominal operational conditions in a three-dimensional domain using the ANSYS Fluent software. The process of spraing liquid fuel components (T-1 kerosene and oxygen) by monopropellant injectors was simulated using a model of discontinuous phases. The simulation results (pressure, temperature and velocity) were compared with the data of analytical thermogasdynamic calculation results and experimental results for pressure in chamber and gas temperature near the wall. The difference between the simulation results and the experimental results does not exceed 8%. Thus, it was shown that it is possible to use the mechanism z77 and hybrid method for determining spray parameters of a swirl atomizer presented in this paper to obtain accurate simulation results of the kerosene T-1 and oxygen spray and combustion processes of the investigated liquid-propellant rocket engine.

Numerical Simulation and Analysis of Semi-Industrial Retrofit for Tangentially Fired Boilers with Slag-Tap Technology

High-alkali Zhundong coal presents significant challenges for power generation, due to its propensity for fouling and slagging. This study investigates a retrofit of a 300 MW tangentially fired boiler with the integration of a slag-tap chamber to improve combustion performance. Computational fluid dynamics (CFD) simulations are employed to examine the influence of this modification on combustion dynamics and the effects of Zhundong coal blending ratios on heat and mass transfer. The results demonstrate that the retrofit facilitates stable airflow recirculation, optimizing combustion efficiency with a peak temperature of 2080 K in the combustion chamber. The flue gas temperature decreases to approximately 1650 K upon exit, which can be attributed to the slag catcher cooling. The integration of the liquid slagging chamber significantly mitigates slag formation, while enhancing oxygen and CO2 distribution throughout the furnace. As the blending ratio of Zhundong coal increases, oxygen concentrations rise in the bottom burner region, indicating improved air–fuel mixing. With a 30% Zhundong coal ratio, the combustion chamber temperature increases by 3%, and flow velocity in the upper and middle furnace sections decreases by 15%, leading to enhanced combustion intensity. This retrofit demonstrates substantial improvements in combustion stability, slagging control, and the efficient utilization of high-alkali coal.

Design and simulation of a simple greenhouse dryer and Peltier thermoelectric module under independent and combined operating conditions

Abstract India is a suitable country for cultivating several food produce, and most of them are seasonal. To make the food produce available in off seasons and to increase their shelf life there is vital need for food processing. Rapid urbanization has imposed a great demand for food due to very less availability of fresh food produce. There is a huge wastage in the food produce as the cultivation land is located far from the end user and time delay due to transportation. There are several food processing methods of which dehydration and cooling play a major role. A simple solar greenhouse dryer and Peltier thermoelectric cooling was designed and studied using COMSOL and EJS tool. The performance study integrating both systems was analysed and reported. The models were considered to work solely on solar energy. Solar thermal energy for dehydration and solar photo voltaic for operating the Peltier device. Studies on performance of the designed systems were carried out along with scope for performance improvement. The simulation studies revealed a 1.439 oC increase in drying chamber temperature by integrating the heat parameter of the Peltier thermoelectric cooler. At 40 K temperature difference the Peltier thermo electric module attained optimal performance. From the analysis using EJS tool, the maximum and average air temperatures inside the dryer were found to be 65 oC and 57 oC, the COP and cooling capacity of the Peltier thermoelectric model were high at 800 W/m2 solar radiation.

Design Modification of the Retort Burner for Phytomass in a Small Heat Source

AbstractPhytomass, a renewable energy source, faces the challenge of ash agglomeration due to its low ash fusion temperature. To address this, chemical modification (adding additives) and co-combustion with other fuels are explored. This study focuses on combustion of phytomass with wood biomass and mechanical modifications to the combustion chamber. The goal is to maintain the chamber temperature below the ash fusion point. Modifications included a modulated burner and water cooling. Combustion of phytomass with wood biomass in the ratio of 60/40, 40/60 and 20/80 had a beneficial effect on increasing the heat source output by 5% and reducing SOX emissions from 61 to 21 mg−3 by adding the wood to hay. The modification of the burner resulted in a reduction of particulate matter from the range 110–140 mg m−3 without cooling to the range 90–110 mg m−3 with cooling depending on the phyto/wood ratio and a reduction in the formation of deposits. By cooling the burner, the temperature at the exit from the combustion chamber was reduced from approx. 560 to 460 °C and at the height above the reaction zone of the flame from 500 to 320 °C. The co-combustion and additional cooling were not such effective, two other modifications were suggested for breaking up or sliding the resulting agglomerates from the surface of the retort. The proposed devices could have potential, as the investment in such a device is more cost-effective than the purchase of a special boiler for burning alternative pellets.

High stability constant temperature chamber upgrade and its characterisation

High stability constant temperature chamber upgrade and its characterisation

Life cycle assessment and thermodynamic performance of biomass-based combined cogeneration

Abstract This study presents a thermodynamic and life cycle analysis of a biomass-based integrated energy system, comprising a biomass gasification cycle, a steam Rankine cycle, and an ammonia fluid Organic Rankine cycle. The primary objective of the system is to efficiently convert olive husk, a sustainable biomass source, into electricity and heating. The gasification process generates syngas, which fuels a gas turbine, producing high-temperature exhaust that drives a Rankine cycle. The thermodynamic analysis indicates that the overall system achieves an energy efficiency of 20.85% and an exergy efficiency of 11.70%. The Rankine cycle exhibits an energy efficiency of 23.91%, while the Organic Rankine cycle demonstrates a higher exergy efficiency of 68.87%. Parametric studies reveal that increasing the combustion chamber temperature significantly enhances system efficiency and output, with energy efficiency rising linearly as the temperature increases from 800 °C to 1000 °C. Additionally, the analysis emphasizes the importance of the compressor's compression ratio on system performance. A life cycle assessment conducted using the ReCiPe methodology evaluates the environmental impact of the system throughout its lifecycle, revealing critical insights into its sustainability. This comprehensive evaluation highlights the potential of utilizing agricultural waste, such as olive husk, to produce renewable energy, thereby supporting environmental sustainability and waste management goals. The findings underscore the viability of the proposed system for enhancing energy production while minimizing environmental impacts, making it a promising solution for renewable energy generation in regions with abundant biomass resources.