Research on the application of temperature and humidity field simulation to environmental monitoring in museums

Aiming at saving defects and cracks of dissimilar metal materials laser welding, the finite element analysis of temperature field and new welding process of stainless steel/Al, stainless steel/Cuwere developed in this work.Taking stainless steel/Al, stainless steel/Cu dissimilar materials laser welding for example, the physical model was established, and the finite element simulation of three-dimensional temperature field of laser welding was carried out based on Abaqus CAE. The results show that the simulation of temperature field provides reference for experimental process parameters, fiber laser welding is applicable to stainless steel/Cu, stainless steel/Al with lower laser welding defect.The process parameters were optimizedto achieve better welding quality and solve welding defects.The accurate prediction of temperature field distribution in dissimilar materials laser welding is great significance for practical process guidance.

In thermal fatigue test, the key point is whether the temperature field on the top surface of cylinder head induced by the heat source can well match it in real service. In order to produce the target temperature field in service which is measured by thermocouples, shaped laser beam generated by diffractive optics element (DOE) is chosen as the heat source to irradiate on the top surface of cylinder head. The DOE is designed based on the Gerchberg-Saxton (GS) algorithm and the simulated temperature field is calculated by finite element model (FEM). The results show that the simulated and experimental temperature field can well match the target one which demonstrates that this method is feasible to produce the target temperature field and can be used in thermal fatigue test.

Accurate meteorological fields and applicable air quality models are important ways to optimize air pollution simulations. To improve the accuracy of winter air pollution models in the Sichuan basin, we conducted a meteorological field simulation using 25 sets of parameterized scheme combinations in the Weather Research and Forecasting (WRF) Model. Based on the optimal parameters, the air pollution levels were simulated using AERMOD and CALPUFF models in a local large steel plant, and the data were verified by comparing the data from four National Ambient Air Monitoring Stations (NAAMS). The results indicated that the WRF model parameters had substantial effects on the simulation of the ground wind field, high-altitude wind field, and ground humidity field. In contrast, the parameters had no significant effect on the simulation of the ground temperature field, high-altitude temperature field, and high-altitude humidity field. The combination of the SLAB land surface process scheme and Dudhia shortwave radiation scheme with four boundary layer schemes, namely YSU, ACM2, BouLac, and MRF, could well-simulate the trends of winter surface wind, temperature, and humidity fields in Sichuan basin. The simulation results were analyzed by combining the statistical parameters of high-altitude wind, temperature, and humidity. The group 1 parameter scheme was applicable to simulate the meteorological field of Dazhou. Group 13 and Group 17 parameters were applicable to simulate the meteorological fields in Chengdu during the day and night, respectively. The correlation between CALPUFF simulation and monitoring value was better than that for AERMOD. CALPUFF was more accurate than AERMOD when referring to the monitoring data from NAAMS No.3. In addition, the simulation quality of CALPUFF was slightly better than that of AERMOD with reference to data from NAAMS No.2. Using air pollutant monitoring data from NAAMS as a reference, the simulated results of CALPUFF on NOx and PM10 were improved compared to AERMOD at all four stations. Data from the Q-Q diagram indicated that the simulated results of CALPUFF on SO2, NOx, and PM10 were closer to the monitored values compared to those of AERMOD.

A finite difference scheme for direct numerical simulation of turbulent velocity, pressure, and temperature fields in plane channels and annuli is described. The fluid is incompressible and has constant density and diffusivities. The method is an extended and revised version of an earlier one. It now includes simultaneous simulation of the temperature field and employs a revised subgrid scale model which has been extended to allow for moderately high Reynolds numbers (Re > 10,000) and poorly resolving grids. The purpose of this paper is to report and demonstrate the improved capabilities of the method.

A three-dimensional model of a circular casting mold with a vibrating nucleus generator was established, and the characteristics of temperature and flow fields during the solidification process of ferritic stainless steel Cr17 in the casting mold were analyzed using finite element and finite difference methods. A standard k-ε turbulent current model was adopted to simulate the temperature field, and a standard k-ε model in Reynolds-averaged Navier–Stokes equations (RANS) was employed to deal with the flow field. The temperature field diffuses outward with a positive temperature gradient. Low degrees of undercooling can prevent solidified shells from forming rapidly on the surface of the nucleus generator. The temperature perpendicular to the direction of vibration is lower than that in the direction of vibration. The flow field exhibits a heart-shaped distribution and spreads gradually outward. The uniform distribution of grains can be achieved at three different frequencies of vibration. The results show that the degree of undercooling affects the distribution of the temperature field while the frequency of vibration affects the flow field significantly. Under the conditions of undercooling of 540 K and vibration frequency of 1000 Hz, the region perpendicular to the vibration direction of the nucleus generator is the optimum area for equiaxed crystal formation.

The APDL language of ANSYS software is used to write program to realize the moving load of weld heat source. The thermal-elastic-plastic finite element method for multi-layer and multi-pass welding process was used to simulate the temperature and stress fields of the V-groove Q235 steel plate butt joint with a thickness of 12 mm. It is concluded that in the welding process, the maximum temperature field does not appear at the center of the heat source, but around the heat source. The farther the free end is from the weld zone after welding, the larger the deformation is. After welding, the overall stress on the upper surface of the weld is larger than that on the middle and lower surface of the weld. Post-weld stress mainly concentrates at the bottom of the weld, i.e. the bottom of the V-shaped opening, and tends to increase from small to large in the direction of thickness.

Deep-time temperature field simulation of hot dry rock: A deep learning method in both time and space dimensions

Based on finite element method(FEM), with general simulation software ANSYS FLOTRAN-CFD module as the platform, using three-dimensional SOLA-VOF method, set the velocity, pressure and temperature boundary conditions and initial conditions reasonably, simulate temperature field, flow field and free surface of Mold Filling process. To simulate the flow of molten metal more factually, mesh dividing method that suited the Liquid simulation was studied, and important thermophysical properties of viscosity and density used the form of function change with temperature. The least square method was used to fit viscosity and density function and these functions were given to boundary conditions. Analyzed the relationship between temperature field and flow field according to simulation result, and get the conclusion that the node temperature depends on filled state of elements attached. At the same time, Get the temperature field at the end of mold filling process, which provides accurate initial temperature field for temperature field and thermal stress field simulation of solidification process. Also provide valuable reference for numerical simulation of Mold Filling process and solidification process of similar part.

Low flow natural circulation regimes are realized in many practical applications and the existence of the reliable engineering and design calculation methods of flows driven exclusively by buoyancy forces is an actual problem. In particular it is important for the analysis of start up regimes of passive safety systems of nuclear power plants. In spite of a long year investigations of natural circulation loops no suitable predicting recommendations for heat transfer and friction for the above regimes have been proposed for engineering practice and correlations for forced flow are commonly used which considerably overpredicts the real flow velocities. The 2D numerical simulation of velocity and temperature fields in circular tubes for laminar flow natural circulation with reference to the laboratory experimental loop has been carried out. The results were compared with the 1D modified model and experimental data obtained on the above loop. The 1D modified model was still based on forced flow correlations, but in these correlations the physical properties variability and the existence of thermal and hydrodynamic entrance regions are taken into account. The comparison of 2D simulation, 1D model calculations and the experimental data showed that even subject to influence of liquid properties variability and entrance regions on heat transfer and friction the use of 1D model with forced flow correlations do not improve the accuracy of calculations. In general, according to 2D numerical simulation the wall shear stresses are mainly affected by the change of wall velocity gradient due to practically continuous velocity profiles deformation along the whole heated zone. The form of velocity profiles and the extent of their deformation in its turn depend upon the wall heat flux density and the hydraulic diameter.

With preheating wire by resistance heat, laser hot wire welding improves process stability and wire deposition efficiency, which gives broad potential applications in surfacing and narrow gap welding. It is a critical issue to control the temperature field of preheated wire in this process. Whether the temperature is so high that the wire fuses outside molten pool or so low that the wire cannot melt timely in the molten pool, results in poor wire transfer stability and bad weld formation. This paper is purposed to calculate the wire temperature field for the prediction of wire transfer stability under various welding parameters. A transient heat conduction model is set up. Heat sources of the wire include resistance heat and reflected laser, and the heat source of molten pool is laser. All heat exchanges are considered as the heat boundary conditions. The calculated temperature of wire part outside the molten pool is verified by infrared ratio temperature measurement. The calculated temperature of wire part in the molten pool is verified by measurement of the molten pool size. Combining the wire temperature field and welding process observed by the high speed imaging, the temperature criterions of wire transfer stability are obtained. Thus, numerical simulation of the wire temperature field can be used to predict the wire transfer stability under various welding parameters in laser hot wire welding.

Simulation of temperature field and residual stress in high-power laser self-melting welding process of CLF-1 steel medium-thick plate

Simulation of temperature field during nanoscale orthogonal cutting of single-crystal silicon by molecular statics method

Measurement and simulation of temperature and velocity fields during the cooling of water in a die casting model

Differential sensitivity analysis and multi-variant simulation of formation pressure and temperature in heterogeneous media

Finite element analysis(FEA) simulation of temperature and stress field was applied in dry-type transformer casting, curing, and cooling process in this paper. Considering to the material's performance changing along with temperature, the paper adopted nonlinear analysis. A 3D FEA model of the dry-type transformer winding transient temperature field and thermal-stress field was theoretically built, and a mathematical model of the initial condition, boundary condition, and latent heat disposal was built as well, then A FEA analysis was finished for the stress frame 3D temperature field and thermal-stress field of the typical winding. The result indicated that the numerical simulation can basically reflect the dynamic changing of the temperature and stress field in the casting, curing and cooling process, and it nicely tallied with the actual measurement. (5 pages)