Thermal Equilibrium Calculation Research Articles

Introducing metal oxide as solid oxygen carrier for energy release enhancement of boron suspension fuel

Boron (B) suspension fuel is a novel high-density fuel for aerospace propulsion. However, it suffers from significant incomplete energy release of B during combustion, which seriously restricts its practical application. This study focuses on the key causes of this problem, insufficient oxygen supply, and proposes to introduce metal oxides (MOx) as solid oxygen carriers to form B-MOx and replace pure B to enhance the energy release characteristics of B suspension fuel. TG-DSC analysis is conducted to sort out CuO as the optimal additive for B oxidation enhancement and its enhancement mechanism is analyzed with thermal equilibrium calculation. It was found that CuO could generate active O atoms through two-step reduction, thus achieving efficient oxygen supply for B and reduce its initial reaction temperature from 810 °C to 661.7 °C with an optimal B-CuO ratio of 1:1. CO2 laser ignition experiment and combustion residue analysis are conducted to analyze the combustion characteristics of B-CuO/JP-10 suspension fuel. Compared with original B/JP-10 suspension fuel, B-CuO/JP-10 suspension fuel presents much higher combustion intensity with local explosion after ignition, and a second stage of intensive energy release is realized with the reignition and explosion of solid agglomerate. The oxidation of JP-10 and B are enhanced with no incomplete oxidation product found in the residue. The enhancement mechanism of CuO on B suspension fuel is proposed including the generation of active radical, efficient internal oxygen supply and enhanced external oxygen supply.

Feasibility Study on A Novel Waste Heat Recovery Process of Industrial Waste Salt Based on High Temperature Melting Dry Method

Industrial waste salt is mainly produced by industrial production processes of pesticides, drug synthesis, printing and dyeing, as well as solid-liquid separations, concentration and crystallization of solution, and sewage treatment, etc. At the present stage, the annual output of waste salt in China has exceeded 2.0×107 tons and the high-temperature melting method is considered to be a promising treatment method, but there are problems such as molten salt adhesion and agglomeration, unused high-temperature sensible heat, and waste of water resources. A novel process for waste heat recovery by high temperature melting dry method is proposed in this paper, using a combination of centrifugal granulation and waste heat recovery to dispose high-temperature molten salt and effectively recover heat. Through thermal equilibrium analysis and calculation, the waste heat recovering efficiency of the waste heat recovery using the novel process can reach up to 98%. Taking the annual treatment of 100,000 tons of waste salt as an example, the benefits of effective heat recovery converted to standard coal could be approximately 5 billion. While efficiently utilizing waste heat resources, the novel process brings considerable economic benefits to enterprises, has good industrial application prospects, and helps to advance the process of national hazardous waste solid waste treatment.

Ash deposition of Zhundong coal in a 350 MW pulverized coal furnace: Influence of sulfation

The huge reserve of Zhundong (ZD) coal makes it important for energy utilization of China. However, big concerns on fouling and slagging in pulverized coal-firing boilers were risen due to its high alkali content. It’s important to investigate deposition in different heating surfaces of a boiler burning ZD coal. In this paper, XRF, XRD, ICP-OES were conducted to analyze the properties of ash deposits collected from different heating surfaces in a 350 MW boiler burning 30% Wudong (WD) and 70% Wucaiwan (WCW) coals. Thermodynamics calculations were applied to study the mineral composition of coal ash in the range of 200–1600 °C under different coal co-firing ratio. The analytical results of the ash deposits showed that in medium-temperature (800–1100 °C) flue gas zone (FR and FS), ash deposits have higher sulfate content. While in high temperature flue gas zone (WW and PS), ash deposits have higher Si/Al content and lower S content. The Na/S contents in FR (~1000 °C) are much higher than in other deposits. The thermal equilibrium calculation results showed that a large amount of liquid Na2SO4 and CaSO4 will be generated when burning WCW coal. Co-firing WD and WCW coals can reduce the amount of sulfate (l/slag) formation and the co-firing ratio greatly influence the elimination effect. It can be speculated that not all the sulfates in the ash deposits are formed in flue gas. The sulfation of the Na-containing minerals condensed on the heating surfaces will promote the ash deposition.

UWGeodynamics: A teaching and research tool for numerical geodynamic modelling

The UWGeodynamics module facilitates development of 2D and 3D thermo-mechanical geodynamic models (Subduction, Rift, Passive Margins, Orogenic systems etc.). It is designed to be used for research and teaching, and combined the flexibility of the Under- world Application Programming Interface, (Moresi, Dufour, & Muhlhaus, 2002, Moresi, Dufour, & Muhlhaus (2003), Moresi et al. (2007)) with a structured workflow. Designing geodynamic numerical models can be a daunting task which often requires good understanding of the numerical code. UWGeodynamics provides a simple interface with examples to get you started with development of numerical models. Users can start designing their models without any pre-existing knowledge of programming. Expert users can easily modify the framework and adapt it to more specific needs. The code can be run in parallel on multiple CPUs on personal computers and/or High Performance Computing systems. Although UWGeodynamics has been primarily designed to address geodynamic problems, it can also be used to teach fluid dynamics and material mechanics. UWGeodynamics uses the flexibility of the Python language and the Jupyter Notebook environment, which allows leveraging the wide range of scientific libraries available from the Python community. It also facilitates the coupling with existing scientific Python modules such as Badlands (Salles, Ding, & Brocard, 2018). The functionalities include: • Dimensional input values, using user’s choice of physical units. • Automated and transparent scaling of dimensional values. • Sets of predefined geometries that can be combined to define the initial geometry of a model. • Handles Newtonian and non-Newtonian rheologies (Viscous, Visco-plastic and Visco-elasto-plastic). • Database of common rheologies used in geodynamics, which can be personalised / extended by users. • Simple definition of kinematic, stress, and thermal boundary conditions. • Lithostatic pressure calculation • Thermal equilibrium (steady-state) calculation. • Pseudo Isostasy using a range of kinematic or stress boundary conditions. • Partial melt calculation and associated change in viscosity / heat production. • Simple definition of passive tracers and grid of tracers. • Simple Phase changes • 2-way coupling with the surface processes model pyBadlands (Salles et al., 2018). UWGeo comes with a series of examples, benchmarks and tutorial setups that can be used as cookbook recipes. They provide a wide range of teaching materials useful to introduce numerical geodynamic modeling to students. New functionalities are constantly being added to the code and contributions are more than welcomed. You can access the full documentation online at https://uwgeodynamics. readthedocs.io

Thermodynamic Equilibrium Calculation of Oxygen-Fuel Process of Calcium Carbide Production

The oxygen-fuel process of calcium carbide production refers to the application of oxygen-enriched combustion technology in production of calcium carbide and the method was introduced. The material and thermal equilibrium calculation of this method were done, and compared with electric arc process. The power consumption was greatly reduced and the production temperature of CaC2was reduced, the more economic income of the method can be gained through the comparison, at the same time which can provided theoretical support for the follow study of this method.

Refining Tungsten Purification by Electron Beam Melting Based on the Thermal Equilibrium Calculation and Tungsten Loss Control

AbstractElectron beam melting (EBM) technology has been considered as one of the key steps for preparing high purity tungsten, and reasonable setting of process parameters is the premise. In this paper, the optimum process parameters obtained from thermal equilibrium calculation and evaporation loss control of tungsten are presented. Effective power is closely related to melting temperature, and the required power for maintaining the superheating melt linearly increases with the increase of melt superheat temperature. The evaporation loss behavior of tungsten is significantly influenced by melting rate and melting temperature. Analysis of experiments show that the best results are realized at melting rate of 1.82 g/s, melting temperature of 4200 K, and the corresponding melting power of 130 kW, in which the main impurity elements in tungsten, such as As, Cd, Mg and Sn, present high removal ratio of 90%, 95%, 85.7% and 90%, respectively.

Preliminary Development of Thermal Power Calculation Code H-Power for a Supercritical Water Reactor

SCWR (Supercritical Water Reactor) is one of the promising Generation IV nuclear systems, which has higher thermal power efficiency than current pressurized water reactor. It is necessary to perform the thermal equilibrium and thermal power calculation for the conceptual design and further monitoring and calibration of the SCWR. One visual software named H-Power was developed to calculate thermal power and its uncertainty of SCWR, in which the advanced IAPWS-IF97 industrial formulation was used to calculate the thermodynamic properties of water and steam. The ISO-5167-4: 2003 standard was incorporated in the code as the basis of orifice plate to compute the flow rate. New heat balance model and uncertainty estimate have also been included in the code. In order to validate H-Power, an assessment was carried out by using data published by US and Qinshan Phase II. The results showed that H-Power was able to estimate the thermal power of SCWR.

Effects of temperature on stress corrosion cracking behavior of stainless steel and outer oxide distribution in cracks due to exposure to high-temperature water containing hydrogen peroxide

Cracking growth tests were conducted in high-temperature water containing hydrogen peroxide (H2O2) at 561–423K to evaluate the effects of H2O2 on stress corrosion cracking (SCC) of stainless steel (SS) at temperature lower than the boiling water reactor (BWR) operating temperature. Small compact tension (CT) specimens were prepared from thermally sensitized type 304SS. Despite the observation of only a small portion intergranular SCC (IGSCC) near the side groove of the CT specimen at 561K in high-temperature water containing 100ppb H2O2, the IGSCC area expanded to the central region of the CT specimens at 423 and 453K. Effects of H2O2 on SCC appeared intensely at temperature lower than the BWR operating temperature because of a reduction in the thermal decomposition of H2O2. To estimate the environment in the cracks, outer oxide distribution on the fracture surface and the fatigue pre-crack were examined by laser Raman spectroscopy and thermal equilibrium calculation was performed.

Study on the thermal stability of 2-hexyne, 1-pentyne, ethyl isocyanide, and n-butyl isocyanide as sulfur-free gas odorants

In Japan, tert-butyl mercaptan (TBM) is mainly employed as an odorant of LPG. However, the sulfur component in TBM gives the adverse effect for environment and human body and/or has a negative impact on reforming catalyst of fuel cell and other types of cogeneration systems. In this way, the development of sulfur-free odorant is expected. This study focuses on the thermal stability and combustibility of 2-hexyne, 1-pentyne, n-butyl isocyanide (BIC), and ethyl isocyanide (EIC) that is expected as the candidate odorants. As the result of DSC measurement, the comparison of TDSC indicated that 2-hexyne and 1-pentyne are more thermally stable than BIC and EIC. However, in 2-hexyne and 1-pentyne, the slight exothermic peaks were observed at lower temperature region before those main exothermic peaks. In 2-hexyne, copper or aluminum increased the heat amount of that slight exothermic peak observed before main peak. In 1-pentyne with zinc, TDSC was approximately decreased to 279 °C from 337 °C of 1-pentyne alone. As the results of ARC measurement, in the presence of oxygen, the exothermic heat of 2-hexyne and 1-pentyne was observed at approximately 50–100 °C. This heat release may be corresponding to the slight heat release observed by DSC, and it thought to be results from the reaction with atmospheric oxygen. In this way, for the practical application of 2-hexyne and 1-pentyne as odorants, it is important to suppress the invasion of oxygen in the cylinder to low as much as possible in respect of the storage of the candidate odorant. As a result of thermal equilibrium calculation, even if either candidate odorant is added at about 100 ppm, there is little influence on propane combustibility from the adiabatic flame temperature, species of combustion gas and their yields.

Identification of SH [FORMULA][F]Δv=1[/F][/FORMULA] Ro-vibrational Lines in R Andromedae

We report the identification of SH Deltav=1 ro-vibrational lines in the published high-resolution infrared spectrum of the S-type star R Andromedae. This is the first astronomical detection of this molecule. The lines show inverse P Cygni profiles, indicating infall motion of the molecular layer due to stellar pulsation. A simple spherical shell model with a constant infall velocity is adopted to determine the condition of the layer. It is found that a single excitation temperature of 2200 K reproduces the observed line intensities satisfactorily. SH is located in a layer from 1.0 to approximately 1.1 stellar radii, which is moving inward with a velocity of 9 km s-1. These results are consistent with the previous measurements of CO Deltav=3 transitions. The estimated molecular abundance SH/H is 1x10-7, consistent with a thermal equilibrium calculation.

Astrophysics of Gaseous Nebulae and Active Galactic Nuclei

Photoionization equilibrium thermal equilibrium calculation of emitted spectrum comparison of theory with observations internal dynamics of gaseous nebulae interstellar dust H II regions in the galactic context planetary nebulae nova and supernova remnants active galactic nuclei - diagnostic and physics active galactic nuclei - results.

Pressure Oscillation in Subcooled Decompression under Temperature Gradient

In the subcooled decompression experiments of water in a vertical tube under a temperature gradient, a violent pressure oscillation was observed. By varying the gradient conditions it was ascertained that this pressure oscillation was due to the existence of the large temperature gradient in the system, and that it occurred in the low temperature region of the system. The generation of the pressure oscillation could be explained by assuming a reflection surface for the pressure wave caused by the blowdown. Two positions of the reflection surface were experimentally obtained from the structure of oscillatory pressure behavior and by computing the autocorrelation function of the pres- sure curve. In the system of a linearly descending temperature distribution, a flashing occurred partially and those two values were in good agreement with the position of the phase boundary generated just after the passage of the decompression wave. The conventional thermal equilibrium model could not completely explain this oscillation. The anomalous pressure peaks appeared in the calculated pressure curve resulting from the prompt flashing in the second supersaturated region. Photographic observation showed that this region was kept in the supersaturated liquid state during the oscillation and that a flashing was delayed. Introduction of the flashing delay time into the thermal equilibrium calculation has well succeeded to reproduce the oscillatory pressure behavior.

Heat of transport in solids. III. Computer simulation of vacancy in an FCC crystal

For pt.II see ibid., vol.10, p.3051 (1977). Uses computer simulation to study the evolution of the time-dependent energy current J(t) for a vacancy in a model FCC system. In view of the problems arising in the thermal-equilibrium calculation of J(t), the simulation is performed at zero temperature, using the augments of a previous paper to justify this procedure. The authors present an analysis which accounts for the main qualitative features of the simulated J(t); over the most important time region, a reasonable approximation to J(t) can be given in terms of dynamics of the hopping particle alone. They use the numerical results to estimate a value for the heat of transport of the model and discuss the relation between this and experimental values.