A high-speed rail tapered bearing temperature calculation model considering contamination particles

Even when an estuary is at steady state, it shows the typical features of a sink for contaminants, although input from rivers into the estuary may result in equal output from the estuary to the sea, thus in such estuaries accumulation of material is practically insignificant. The essential properties which determine the processes and transfer of contaminants to particulate matter are the chemical properties of the contaminant, the specific surface of particulate matter, its composition and its specific surface exchange capacities. A correlation exists between these factors. It is very essential to understand the complete picture of how compounds are sorbed to particulate matter, and not only part of it. For estuaries with a long freshwater-seawater mixing section and a turbidity maximum, the question can be posed whether the distribution of the dissolved and particulate contaminants along the estuary is conservative, meaning that the total inflow of contaminants (particulate and dissolved) from the river equals the discharge from the estuary into the sea, while there is no loss to or gain from the bottom. Model calculations have been made to solve this problem for different adsorption and complexing processes. Whether tropical estuaries are sinks or sources has to be answered in a time context. A tropical estuary newly contaminated will be a sink for a very long period, although equilibrium between input and output may be sooner obtained than in temperate climates. It may afterwards become a source, where the bottom sediments act as a buffer with very long turnover times, up to 1000 years.

We have systematically investigated the electron emission of various kinds of polycrystalline CVD-diamond films by means of a Field Emission Scanning Microscope with /spl mu/m resolution, which contains an in situ scanning electron microscope. Besides the previously reported enhanced field emission from particulate contamination and other surface irregularities at electric fields between 2.5 and 150 MV/m, an almost uniform emission over the film surface was detected on all samples at applied electric fields above 220 MV/m. The pure p-doped Si-100-substrate requires, in comparison, much higher fields for electron emission. Field emission at electric fields as low as 70 MV/m was achieved from Si-dots covered with diamond-caps. The comparison of high-resolution line scans with model calculations strongly suggests the observed intrinsic field emission of CVD-diamond combined with geometrical field enhancement as responsible emission mechanism of these structures.

Process design of multi-stage wet wire drawing for improving the drawing speed for 0.72 wt% C steel wire

During deep-water oil and gas explorations, the dual gradient drilling (DGD) technology provides solutions to problems caused by the narrow density window and the shallow gas by controlling the pressure profile in the wellbore. A transient temperature calculation model is established with consideration of the heat generated by the pump in the specific processes of the DGD systems. Besides, the momentum equation is modified by considering the lift force of the pump on the drilling mud in the pressure calculation. An iterative scheme for the coupled temperature and pressure calculations is developed. Besides, the transient temperature and pressure are analyzed for a deep-water well in South Sea. It is shown that the bottom-hole pressure varies significantly with the transient temperature in the wellbore, and the change of the bottom-hole pressure in the case of the DGD (626 kPa) is larger than that in case of the conventional drilling (115 kPa) due to the constant inlet pressure of the subsea pump. With this fact in mind, an adequate safety margin is strongly recommended to be considered during the hydraulic parameter design of the DGD. Our results further show that the DGD can significantly extend the operation range of the drilling fluid density, and the advantage becomes more obvious in a deep water.

In the context of the Energy Internet, in order to save energy, protect the environment and achieve green development, the consumption of renewable energy nearby has become the future development trend of the traction power supply system for electrified railways. Photovoltaic power generation has high reserves and mature technology. If it is combined with energy storage, it can be widely used in railway traction power supply systems. So far, there is no literature on the impact of integrated solar energy storage integrated into the high-speed rail traction power supply system on traction transformers. After the photovoltaic is connected, it can play a role in peak shaving to a certain extent when the transformer is operating in an overload state, thereby reducing the damage to the transformer caused by overload operation, reducing the installation capacity required by the traction transformer, and extending the transformer's life to a certain extent. service life. This report first uses MATLAB/SIMULINK to build a comprehensive energy power supply system model, selects typical high-speed rail loads to obtain the current waveform of the secondary side of the traction transformer; and then combines the transformer hotspot temperature calculation model, aging rate and life loss calculation model to obtain the transformer after photovoltaic connection. The effect of aging rate.

In order to develop more energy-saving control algorithm, an electric vehicle air conditioning system model is established. Electric air conditioning system compressor model, compartment thermal load model, heat transfer model, controller model and temperature calculation model are built based on certain pure electric commercial vehicle air conditioning system. A compound control method applying fuzzy and PID theory is put forward in this paper. A secondary development of EV model is established in ADVISOR. As the result shows, the Fuzzy-PID control method is more accuracy and consuming less energy. Optimized control algorithm for air conditioning is realized.

In order to develop more energy-saving control algorithm, an electric vehicle air conditioning system model is established. Electric air conditioning system compressor model, compartment thermal load model, heat transfer model, controller model and temperature calculation model are built based on certain pure electric commercial vehicle air conditioning system. A compound control method applying fuzzy and PID theory is put forward in this paper. A secondary development of EV model is established in ADVISOR. As the result shows, the Fuzzy-PID control method is more accuracy and consuming less energy. Optimized control algorithm for air conditioning is realized.

New optimized model for water temperature calculation of river-water source heat pump and its application in simulation of energy consumption

The purpose of this paper is to discuss the variation of wellbore temperature and bottom-hole pressure with key factors in the case of coupled temperature and pressure under multi-pressure system during deep-water drilling circulation. According to the law of energy conservation and momentum equation, the coupled temperature and pressure calculation model under multi-pressure system is developed by using the comprehensive convective heat transfer coefficient. The model is discretized and solved by finite difference method and Gauss Seidel iteration respectively. Then the calculation results of this paper are compared and verified with previous research models and field measured data. The results show that when the multi-pressure system is located in the middle formation, the temperature of the annulus corresponding to location of the system is the most affected, and the temperature of the other areas in annulus is hardly affected. However, when the multi-pressure system is located at the bottom hole, the annulus temperature is greatly affected from bottom hole to mudline. In addition, the thermo-physical parameters of the drilling fluid can be changed by overflow and leakage. When only overflow occurs, the annulus temperature increases the most, but the viscosity decreases the most. When only leakage occurs, the annulus temperature decreases the most and the viscosity increases the most. However, when the overflow rate is greater than the leakage rate, the mud density and bottom-hole pressure increase the most, and both increase the least when only leakage occurs. Meanwhile, bottom-hole pressure increases with the increase of pump rate but decreases with the increase of inlet temperature. The research results can provide theoretical guidance for safe drilling in complex formations such as multi-pressure systems.

Numerical investigation of photovoltaic performance improvement using Al2O3 nanofluid

This paper presents results of a study of the conjugate heat transfer (CHT) to calculate the metal temperature for a film-cooled gas turbine blade. ANSYS CFX14.0 code was selected as the computational fluid dynamic (CFD) tool to perform the CHT simulation. The two-equation SST turbulence model with automatic wall treatment was employed. The main flow inlet and exit boundary conditions were deduced from a multi-blade-row CFD code, Fine/Turbo by NUMECA. A core engine test operated at the maximum power condition. Thermocouples were used to validate the blade metal temperature calculations. The blade temperature comparison between test data and CHT predictions was in good agreement except at the suction side near the leading edge region. The pressure, temperature and Mach number distributions for blade internal and external flows were presented and examined. The streamline contours of the film flows on the pressure side and suction side were plotted and used to visualize the cooling effectiveness. In order to evaluate the influence of the turbulence model, the thermal results of four additional turbulence models (SA, RNG, K-ε, and SST with transition control) were compared to the test data. The SST model is suggested to be the appropriate turbulence model for the film-cooled blade temperature calculation in this study.

Based on improvement of Swift's black-box thermal-circuit model, this paper establishes a dynamic numerical model suitable for different capacity transformers. According to effect factors of the precision of thermal-circuit model, such as winding losses, oil viscosity changes, heat dissipation conditions, et al, this paper proposed ways to modify the model. The model is proved to be precise by comparing results with factory temperature rise test data.

A new simplified model based on a semi-analytical correlation is proposed in this paper to evaluate the heating radiant slab surface temperature and to examine its thermal behavior under dynamic solicitations. In fact, the surface temperature is a normative design parameter and shall be kept under an upper limit whatever are the running conditions. Experimental measurements and a two-dimensional finite difference model (2D FDM) were carried out to validate the developed simplified model based on two characteristic parameters that are the time constant and the delay time. A Design of Experiments (DoE) method is employed to derive meta-models for the time constant and the delay time in order to compute the surface temperature. The sensitivity analysis shows that the specific heat capacity of the slab material and the heating water flow rate affect significantly the time constant compared to the thermal conductivity and the heating water pipe inner diameter. Moreover, it was found that all these parameters, except the heating water flow rate, have a substantial impact on the delay time. Compared to the experimental results, the maximum relative deviations from the computed surface temperature are within 2.4% for the numerical model and 1.75% for the simplified semi-analytical model. Consequently, the proposed simplified model may be utilized by engineers and designers to quickly estimate the radiant slab surface temperature and heat flux as well as to study its thermal behavior under dynamic running conditions. This model may also be integrated in the thermal building simulation software.

The combined radiation and conduction heat transfer in multilayer perforated insulation material (MLPIM) in orbit is investigated. The energy equation of the reflective screen is established. Combining the finite differential method the model for transient temperature calculation of reflective screens in MLPIM and the model of inner radiation are presented. The space environment is looked as a screen in the model,which is convenient to deal with the boundary condition. Comparing the calculational results by the model in this paper with the calculational and experimental results in the reference at the analogical conditions it is proved that the model is feasible to apply in engineering. The calculational results in another example show the characteristics of the transient temperature and heat loss flux of MLPIM in orbit and of the temperature distribution of the reflective screens with different screen emissivity and perforation coefficient as the temperature is steady. This model provides the theoretical basis and instruction for the thermal performance study and optimum design of MLPIM

Thermal expansion of the workpiece during cylinder boring process is one of the sources causing the bore cylindricity error. To study thermal expansion induced bore distortion, detailed workpiece temperature distribution in cylinder boring is required. Four finite element models, namely, the advection model, surface heat model, heat carrier model, and ring heat model, were developed to predict the workpiece temperature in cylinder boring. Cylinder boring experiments were conducted utilizing the tool–foil and embedded thermocouple experimental approaches to measure the workpiece temperature, predict the temperature distribution using the inverse heat transfer method, and evaluate the capability of the four models in terms of accuracy and efficiency. Results showed an accurate global temperature prediction for all models and a good correlation with the embedded thermocouple experimental measurements. Good correlation was also obtained between the tool–foil thermocouple measurement of machined surface temperature and model predictions. Advantages and disadvantages as well as applicable scenarios of each model were discussed. For studying detailed cylinder boring workpiece temperature, it is suggested to use the ring heat model to estimate the moving heat flux and the heat carrier model for local workpiece temperature calculation.