Research On Heat Transfer Law Of Crude Oil Storage Tank During Jet Heating Process

Petroleum,as the world's most important primary energy,affects the development of industry and the progress of science and technology.As the world's demand for crude oil continues to increase,oil production continues to increase.As a big importer of crude oil,China's crude oil reserves seriously restrict the development of industry.China began to implement the strategic petroleum reserve project in 2004,but it has not yet formed the reserve capacity to meet the national consumption demand for 90 days.With the establishment of large oil storage stations,more and more attention has been paid to the heating method of crude oil in oil storage tanks.As a heating method with high heating rate and less energy consumption,jet heating has been gradually applied to large oil storage tanks.Generally speaking,the jet heating process in the oil storage tank is essentially thermal buoyancy jet.For different oil storage tanks and nozzles,the study of heat transfer and flow characteristics in the process of jet heating is of great significance for the formulation of a reasonable process scheme,the assistance of engineering decision-making,and the enrichment of engineering heat transfer research results.In view of this,this paper adopts the method of combining experiment and numerical simulation to study the heat transfer law of the jet heating process of oil storage tank.Specifically,the following studies are included:Firstly,the simulation experimental system of crude oil storage tank jet heating process is constructed,and its heat transfer law is analyzed.The visualization of flow field is realized based on particle image velocimetry system,and the temperature sensor is used to monitor the temperature data in the storage tank.The experimental system and method of simulating the jet heating process of crude oil storage tank are constructed.Taking the nozzle diameter,bend angle,jet temperature and jet velocity as the influencing factors,the evolution law of the flow field and temperature field in the tank jet heating process under different factors was studied.The Gr number,Pr number and Ra number were used as the basis for quantitative analysis,the main position of heat dissipation is studied and the transfer law of momentum diffusion and heat diffusion under different experimental conditions is analyzed.Secondly,the mathematical model and physical model of jet heating process are established.The heat transfer system of crude oil storage tank jet heating process is constructed.Based on the relevant research,the thickness and material of the boundary are set to simplify the boundary structure.An unstructured grid is used to discretize the solution region.The governing equations of each mesh are discretized based on the finite volume method.Then,the three-dimensional numerical simulation of heat transfer and flow in the process of jet heating is studied.The law of heat transfer and flow in the process of jet heating is studied and analyzed.The evolution law of heat transfer region in temperature field and high velocity region in velocity field is studied and analyzed.The coupling relationship between jet flow and heat transfer is emphatically analyzed.The field synergy theory is introduced to describe the heat transfer efficiency of the jet heating process with the synergistic angle.Finally,the influence law of the influencing factors on the heat transfer efficiency of the jet heating process is analyzed.The control single variable method was used to design the experimental scheme.The field synergy theory was introduced to quantitatively characterize the heat transfer efficiency under different influencing factors.The influence degree was quantitatively calculated by using grey relational analysis method.For the 1×10~4m~3 floating roof tank in the experimental condition,different influencing factors have little influence on the evolution law of temperature field and velocity field.Heating efficiency was characterized by the field synergy theory.In the simulated experimental conditions,the working condition of simulated?48×4mm nozzle diameter,the heating temperature is 70?,30°bend angle,nozzle number is 8,liquid level height is 3 m,jet velocity of 12.277m/s,nozzle angle for 0°,synergistic angle of the minimum,the highest heating efficiency.Based on the grey relational analysis method,the correlation degree is sorted as follows:heating temperature>liquid level height>nozzle number>jet velocity>bend angle>nozzle diameter>nozzle angle.As for the jet trajectory,when the influencing factors have a great influence on the jet velocity,heating temperature and bend angle,the jet trajectory will change accordingly.