Modern automatic assembly puts forward higher requirements for the stability and accuracy of material conveying. In order to meet industrial needs, a piezoelectric vibration that uses a rectangular piezoelectric vibrator as an excitation source and works in a vertical drive mode was designed. Feeder. By simplifying the double⁃cantilever piezoelectric vibrating feeder and establishing its dynamic model, the expressions of natural frequency and device amplitude were derived, and some factors affecting natural frequency and amplitude were analyzed. Use ANSYS Workbench software to analyze the dynamics of the device. The natural frequency of the system was 118.85 Hz, and the harmonic response analysis of the device was performed. The results show that when the driving voltage is 200 V, the system driving frequency is between 116.00～122.00 Hz, and the double cantilever piezoelectric vibration gives The feeder has the ability to transport materials, the vibration amplitude is the largest at the point closest to the resonance point (118.00 Hz), and the transport efficiency is the highest, which can meet the requirements of industrial production.

The corrosion behavior of auxiliary anode under the combined action of alternating current density and cathodic protection were studied. Firstly, the corrosion rate and corrosion image were analyzed by immersion experiment, and the corrosion process was determined. Secondly, the electrochemical behaviors of the auxiliary anode under different conditions were analyzed by electrochemical test, and the corrosion behaviors of the auxiliary anode under different conditions were characterized according to the change of its corrosion kinetic parameters. The results show that the corrosion product layer formed under lower alternating current density overlays on the surface to slow down the corrosion, while the higher alternating current density can break down the corrosion product layer to activate the corrosion reaction. The cathodic protection current causes the corrosion product layer to be in the constant destruction and the generation process, further promotes the corrosion reaction. The results of immersion experiment are in good agreement with those of electrochemical test.

In order to study the interaction of flowing hydrodynamic force, buoyancy, pipe body, gravity of conveying medium and resistance of soil foundation on pipeline, the mechanical analysis model of pipeline under flood was established. The stress and strain of pipeline were calculated by numerical analysis method and finite element method. The results show that the calculation results of the two methods are close. Based on the finite element model, the effects of flood velocity and crossing distance on pipeline stress and strain are analyzed. The results show that when the velocity is greater than 3.0 m/s, the stress and strain of the pipeline increase with the increase of the velocity. When the crossing distance increases, the maximum stress and axial strain of the pipeline at the embankment gradually increase, but the increase decreases.When the crossing distance is less than 160 m, the stress and axial strain of the pipeline in the middle of the river increase with the increase of the crossing distance, and when the crossing distance is more than 160 m, the stress and axial strain decrease slightly with the increase of the crossing distance. The safety assessment of the buried suspended pipeline of Yulin⁃Jinan Railway is carried out. The results show that the immediate stress is 178 MPa, and the suspended pipeline is safe.

The influence of parameters such as fluid velocity, particle size, fluid viscosity, and fluid density on the erosion behavior of blind passages was investigated using computational fluid dynamics (CFD). DPM model was used to calculate the trajectory of solid particles in blind pass, and the effect of particle movement on erosion corrosion rate in blind pass was analyzed.Explore the optimal structure of blind⁃pass pipe to reduce erosion corrosion, and compare the influence of blind⁃pass length on erosion corrosion.The numerical simulation results show that the serious erosion corrosion area is mainly located at the location of inner arch of the blind⁃through pipe. As the fluid velocity increases, the erosion corrosion behavior intensifies, and the erosion corrosion behavior weakens due to the increase in particle size and the viscosity, and the erosion corrosion behavior was the weakest when the blind pass length was 45 mm.

In order to study the dynamic process，damage of liquefied natural gas (LNG) leakage and diffusion(LNG), a Gaussian smoked mixture model with point source continuous leakage modified by Gaussian smoke group model was selected and programmed by MATLAB software to study different grounds. Half of the lower limit of the explosion(1/2LFL), the lower limit of explosion (LFL), and the upper limit of the explosion (UFL) corresponding to different factors, and the influence of the factors such as the effective height of the leakage source on the leakage of LNG gas and the analysis. And the experimental models were verified by Burro No. 9,The results show that the range of the danger area decreases with the increase of the surface roughness. With the increase of the effective height of the leakage source, the concentration of the highest point is decreasing and the danger is reduced at the same time. The scope of the area will continue to decrease.Due to the different wind speed, in the early stage of LNG leakage, the greater the danger area, the greater the wind speed. After the state of the gas cloud is stable, the area of the dangerous area decreases with the increase of wind speed.

Three improved grey forecasting models are constructed to improve the accuracy of traditional forecasting methods. This paper took natural gas load of Beijing from 2007 to 2015 as raw data for modeling, and tested the predicting results of 2016.The traditional Grey Model and the three kind s of improved Grey Model were established to predict respectively，and the optimal model with best precision was chosen to combine with metabolism model which abandons the old data, constantly supplies new data, and repeats modeling. The optimal improved Grey Model was established to predict the annual gas load of Beijing from 2017 to 2020.The results show that the combined model can reduce the interference of the original data to the prediction system, the prediction accuracy meets the actual requirements, and the accuracy is much higher than the traditional gray model. It can truly reflect the development trend of annual natural gas load, and the prediction results are reliable and practical. It can provide reference for natural gas deployment and optimization of the pipeline network.

Urban gas pipeline network is mostly laid underground, which brings difficulties to detecting small leakage.After the leakage,it is prone to poisonous accidents such as poisoning, fire, explosion, etc., which brings hidden dangers to urban public safety.This paper sets up a calculation model for two backfilling methods of layered soil and non layered soil in pipe network,and different physical convection diffusion models are established for different laws of gas diffusion in soil and atmosphere environment.Based on the unsteady leakage model and the CFD software, the paper analysis the buried duffusion separately and analysis the atmospheric diffusion coupling soil and atmosphere.And the study about the effect of back filled soil on the diffusion of gas in soil and atmosphere.The results show that:low⁃ and medium⁃ concentration gas will delay diffusion and produce inflection point through stratified interface. The diffusion rate will increase after the layered interface, and the diffusion rate of gas in the layered soil will be high when the leakage time is greater than 100 s.The atmospheric diffusion rate of methane under stratified soil is not much different between the upwind side wind and the downwind directions. The longitudinal 100 s diffusion rate is larger than that one of the non stratified soil, and the larger the inertial resistance coefficient is, the faster the diffusion is.

For the study of variable diameter tube affects the quantity of sequential oil transportation of the refined oil, applying multiphase flow model, the 90# gasoline and 0# diesel oil as the object of alternate transportations, according to different variable diameter pipeline structure form and different tapered Angle on the oil transportation.The results show that the growth rate of the length of the mixing section decreases obviously and the length of the mixing section decreases for a short time when the mixing oil enters the sudden expansion pipe, then the length of the mixed oil section growth accelerated obviously, but inferior to the level before variable diameter and with the increase of taper Angle, the different length were mixed with different degrees of decreased; after the mixed oil section flows into reducing pipe, the length of the mixed oil section growth obviously larger, and appeared the trend of decrease, but still higher than before the variable diameter, and with the increase of tapered tube taper Angle, the length of the mixed oil section all have varying degrees of increase.

Aimed at the existing steam injection boiler with wet saturated steam, the steam overheating and tube-burst pre-warning device is developed. The judgment basis and algorithm model of steam overheating monitoring are given, and the composition of the design device, component connection and man-machine interface are optimized. According to the physical properties of water and steam, the steam state is divided into four operation conditions: overheating alarm zone, overheating warning zone, operating zone and safety zone. Based on this, the visual coordinate diagram and the overheating monitoring histogram of the steam operating condition monitoring are designed in the man-machine interface. The steam overheating incidents are classified and filtered to make the device more reliable for steam overheating and early warning. Through field application data analysis, the effectiveness of the device is verified.

In order to study the problem of distribution of mixed oil in T-shape pipeline of refined oil products. And the control equation of the sequential transport mixed oil is established by using multiphase flow model, 90 ^# gasoline and 0 ^# diesel are used as the alternate transportation objects. The process of downloading the mixed oil formed by gasoline and diesel under different conveying sequences through the branch pipe is numerically calculated, and the distribution of mixed oil quantity is obtained. The influence of the mixed oil in the main line on the mixed oil section under different conveying sequence is analyzed. The results show that the mixed oil in the main pipeline can be shortened by the appropriate amount of oil in the station provided along the line, which can significantly shorten the length of the mixed oil section and reduce the download pressure on the mixed oil section of the pipeline at the end station.

The calculation of temperature drop was one of the most important parameters in the repair process of hot oil pipeline, and the value played an important role in the pipeline excavation repair plan and oil transportation. The thermodynamic model of unsteady state after excavation was established from the view of thermodynamics, and the simulation was carried out on the basis of a case study of the hot oil pipeline from Songshan to Jinzhou. The influence of the different starting points, excavation length and oil station temperature on the oil temperature of hot oil pipeline was studied combined with CFD in different seasons of excavation operation of hot oil pipeline and the soil temperature field around the changes of numerical simulation analysis. The results of the study could ensure the safe operation of the pipeline under the premise of providing hot oil pipeline excavation repair recommendations and guide the management department to optimize the construction repair plan.

The safety of styrene tank farm whose harm was serious was evaluated by Dow Chemistry Method. According to the actual situation of tank farm, the typical storage tanks to be evaluation units were selected, then the risk coefficient of technologies was analyzed, and the fire-explosion index, exposure radius and regions were calculated. The fireexplosion index and class could be effectively reduced by some safety measures compensating. The results showed that this method could comprehensively and effectively evaluate the potential fire and explosion hazards in the styrene tank farm.

Aiming at the problem in dynamic leakage of urban overhead gas pipeline,considering the impact of different pressure levels on leakage and diffusion, high pressure (2.0 MPa), sub high pressure (1.0 MPa) and medium pressure (0.4 MPa) three kinds of pressure grade pipe to simulate were selected.Firstly, the leakage rate of the critical flow and the sub critical flow were calculated by using the leakage rate calculation mode.Secondly, the leakage rule of different pressure pipelines was obtained.The Fluent software was used to simulate the unsteady state leakage, and the risk range of natural gas diffusion was obtained.The results showed that if the pressure in the tube was greater,the quality of residual gas in pipe and the time of leaking was higher and the risk range of natural gas was lager when the volume of pipe and the diameter of leak were fixed.With the continuous leakage of non steady state, the leakage rate was getting smaller and smaller, the risk of natural gas was also getting smaller and smaller.

Sulfur phosphate was synthesized through the reaction of n-butanol, iso-octanol and phosphorus pentasulfide in the absence of solvent. The reaction condition was optimized by variation of catalyst type, the feeding mode of phosphorus pentasulfide, reaction temperature, pressure and initial reaction emperature. In the mean time, the performance differences of the lubricating additive T202 prepared by sulfur phosphate catalysis was compared with that synthesized with old process. Experimental results showed that the optimal conditions was as follows: the catalyst 4, the phosphorus pentasulfide feeding mode was nine, the reaction temperature was 50～55 ℃, the pressure was 0.07 MPa, initial temperature was 40 ℃, the reaction time was 1 h. Under this condition, the achieved content of sulfur phosphate was up to 99.4%, the zinc content of the lubricating additive T202 prepared by sulfur acid was 11.76%, and the chroma was 0.

According to the technology of situ electrical heating on oil shale, a physical model was established by FLUENT. Numerical analysis of temperature field distribution of oil shale was carried out. In this model, the healing efficiency was increased by time, which was obviously increased when the heating well and oil well exchange heating. When the heating time was less than 3 a, the temperature of oil shale layer was increased steadily. But it did not reach the temperature that oil shale pyrolysis required. When the heating time was greater than 3 a, the temperature of oil shale layer was reached to 350～500 ℃. And it reached the temperature that oil shale pyrolysis required. After pyrolysis, the thermal conductivity, porosity and permeability of oil shale were increased while the temperature was elevated. Therefore, the analysis and control of temperature field of oil shale was helpful to improve the heating efficiency and production of oil shale.

If product oil pipelines were constructed in the areas of complex topography, parts of pipelines would inevitably encounter some problems via the large gap areas. Due to the existence of pipeline crossing point and the physical difference of the transport oil, it may appear the phenomenon of slack flow in the downhill pipeline. According to all kinds of operating conditions, it may appear via the large gap areas. Based on VOF multiphase flow model numeral simulation was built to research the influence of slack flow features for different angles, different pipe diameters and flow velocity. Through the computer analysis, it elaborated the influence factors of the discontent flow phenomenon for product oil in a large gap location. The results provided theoretical guidance for the design of transport pipeline in mountainous areas.

In batch transportation of finished oil products, mixed oil would be produced by adjacent batch oil. The cases of 30°, 45°,60° or 90° for the joint line of the variable diameter part and the straight pipe of the variable diameter pipe were calculated by the CFD software. The conclusion show the relationship and the change law between the angle of the joint of the variable diameter part and the length were researched. The results show that with the angle increased, the mixed oil segment length decreased in the sudden expansion pipe and the opposite conclusion in the reducer, which was coincided with engineering basic phenomenon.

Took the boom of small hydraulic excavator working device as the research object, finite element analysis model was done. Pro/E 3D software was used to build the threedimensional model of the boom of the excavator working device, then imported into ANSYS software through seamless interface software Pro/E and ANSYS software. In addition, ANSYS was used to carry out the static and modal analysis of the boom, and corresponding stress contours, displacement contours, modal frequencies and vibration modes were obtained, which offered theoretical references for the structure optimization design.

 

For the problem of oil leak in different soil particle diameter, using CFD simulation software to establish the soil porous media mid-stream solid coupled mathematical model of phase transitions. The simulation results show that before the leaking, the distribution of isotherms of the steady-state temperature field becomes the sharp of flat circle and the temperature lower from inside to outside. Meanwhile, this distribution does not have obvious changes in the different sizes of soil particles; after the leaking, the isothermal lines in the small particle diameter soil presented divergent patterns with reduction of the distribution from inside to outside. At the same time, with the leakage of oil flowing into the porous medium, the temperature gradient tended to be stable. In large particles soil, because of the low power of oil flow resistance, the change of water which exit in permafrost could happen faster, and the stochastic distribution of the isotherms of the divergent is more obvious. This situation destructed the stable temperature field more seriously.

A 3D CFD model was established. The oil diffusion of lower leakage of the pipe in the soil porosity of 0.45 and 0.47 was simulated and analyzed. The results show that the oil spread to the surrounding area to expand in a way of oval in compact soil. The area, width and depth of spread increase largely in the initial of the leakage. After diffusion several minutes, they are increasing stably over time and the volume of diffusion is in smaller growth rate as the time changed. The oil spread downward expansion over narrow width of the diffusion region in loose soil. Spread width and area growth trends are slow down after. The depth of spread increased larger than former soil and the volume of diffusion were in larger growth rate as the time changed.

 

 

 

Hot oil pipeline and product pipeline with the parallel in the trench for the laying was studied for energy transfer process. Application of finite difference method analyzed the pipeline during normal operation of non-steady-state heat transfer model. And using finite volume method calculated the pipeline in parallel pipelines at different sections around the soil temperature field in numerical calculation. In the west pipeline, Shanshan-sibao, for example, the surface temperature with periodic boundary conditions, and obtained the discipline in different seasons at different locations along the soil temperature field. Research shows that with the cyclical changes of surface temperature, the impact of cold product pipeline to the soil temperature field around hot oil pipeline is different. And the impact on soil temperature field around the side of hot oil pipeline far away from the cold product pipeline is little. With the run-time increasing of pipeline, the impact of cold product pipeline to the soil temperature field surrounding the hot oil pipeline gradually weakened. Simulation results show that it is consistent with the practice. It provides theoretical guidance for the developing maintenance plans and intermittent delivery programs and determining safe shutdown time.

With the example of airport refuel system network, aiming at the characteristics of loop pipe network and dendritic pipeline network, hydraulic transient mathematical model was set up respectively.And use characteristic method to simulate different arrangement of refuel system network of hydraulic transient, the examples simulation results show that hydraulic transient peak pressure of loop pipe network is lower than dendritic pipeline network,and the pressure of each parts of pipeline is even more equilibrium,and stability and reliability of pipeline is better, it can decrease effectively the destruction of hydraulic transient and the effects. Therefore, the using of loop pipe network is more suitable at airport refuel system network.