Aiming at the leakage and diffusion problems of the 35 MPa ultrahigh pressure gas pipeline in densely populated area, the FLUENT software in the threedimensional numerical simulation was used under different climate conditions in the deep buried gas pipeline leak case. And the axial and surface safety area of the hydrogen sulfide and methane was provided when the ultrahigh pressure gas pipeline had leaked under the conditions of different wind speeds. Because of the buoyancy, the natural gas developed in the upward form during the process of diffusion. The wind speed and pressure had different effects on the diffusion process under the different environments. The result was that as the wind speed and pressure was higher, the natural gas was spread to the farther distance. This increased the lowest explosive limit and alerted the concentration range of the natural gas. The research result could provide the effective basis to the stuffs and security management in leakage spot.

Highpressure steam injection method is the major method of exploitation of heavy oil reservoir. In steam injection pipe network, the fluid in steam, liquid and solid phases scoured the bend and led to leakage. Based on the turbulence models, multiphase flow models, discrete phase models and erosion models ,and considering the mutual coupling of the different phases, the numerical simulation of the flow of the three phases in the bend flow was established. The results show that in the steam injection pipelines，as bending degree of the bent pipe increased， the distribution and wall wear area of the liquid phases and particle phases moved backwards step by step，and the value increased accordingly. Moreover, the increase of liquidphase volume fraction in the pipe wall could effectively reduce the surface corrosion of the solid phase.

In flow measurement field, the differential pressure flowmeter was used widely. Adopting highprecision calibration system to calibration differential pressure flowmeter，the flow coefficient of the flowmeter was obtained. And the error analysis of the flow coefficient with scientific method was made to draw calibration result and its error accuracy. The results show that the measurement errors of the flowmeter followed the standard, and the flowmeter could be used for the actual measurement in the field.

In Gas injection pipeline the erosion wear of solid particle in cone throttling element was an important factor for causing failure. In this paper, made by the method of computational fluid dynamics finite volume was used for the numerical simulation of the erosion abrasion and the degree to erosion abrasion and the relationship of the shear stress with the injection volume, particle diameter and the particle content change were researched. The results showed that as the particle diameter increased, the tube wall wear relatively focused on the high speed area, the degree to the cone wear was increased. When the flow rate increased, erosion rate and shear stress were increased. And when the particle concentration increased, the quantity of the erosion abrasion was increased. So the research to the throttling element antifriction corrosion study and throttling element failure prediction would provide the theory guidance.

Spiral separator has the characteristics of simple structure, light weight and wellseparated effect, which becomes one of the commonest centrifugal separator currently. CFD method was used to simulate wateroil separation in spiral pipe under the condition of a variety of entrance velocities and cross section shapes, and obtained a wateroil separation result that for a spiral pipe with circular cross section shape, the separation effect became sharper as the velocity increased, and too fast or too slow velocity both impacted the effect. When they were equal cross section areas, circular had a better effect than laddershaped and square cross sections. Based on the numerical simulation, the result provided a certain theoretical basis for spiral pipe technology.