Modeling And Heat Load Analysis Of Gas Engine Exhaust Manifold

Natural gas internal combustion engines can effectively reduce emissions pollution.In this subject,the vehicle diesel engine is converted into a gas engine of a generator set.Under the premise of missing exhaust manifold design parameters,reverse engineering technology is used to obtain a reasonable three-dimensional reconstruction model of the exhaust manifold.Gas-fired power generation internal combustion engine engineering takes a long time and exhausts The gas temperature is high,in order to further improve fuel economy and increase the reliability of the exhaust manifold.By building a one-dimensional model of the gas engine of the generator set,the exhaust manifold structure was optimized.The study concluded that the exhaust manifold of the original engine was designed with a smaller pipe diameter in order to take into account the performance of low speed,and the exhaust back pressure at 1500r/min was relatively high.It is not suitable for use in modified gas-powered internal combustion engines.On the basis of pipe diameter optimization,the thermal boundary conditions of the exhaust manifold under simulated real operating conditions were obtained,the fluid-structure coupling simulation model was established through the FLuent UDF module,and 5 working cycles were coupled and calculated,and the reconstruction model exhaust manifold was analyzed.The temperature field,thermal stress,thermal deformation and thermal mode of the tube.Under these conditions,the exhaust manifold model is optimized and improved according to the requirements of different schemes.The temperature field,thermal stress,thermal deformation and thermal mode of the two exhaust manifold improvement schemes are compared and analyzed.As a result,it is believed that the thermal deformation of the first scheme increases slightly,and the second structural scheme can further reduce the thermal deformation,which is beneficial to increase the life of the exhaust manifold,and the working frequency of the two schemes will not resonate with the engine.Meet the design requirements of gas-fired power generation internal combustion engines.The modeling and optimization methods in this article can provide reference and guidance for the retrofit design of the exhaust pipe of gas-fired power generation internal combustion engines.The main contents of this paper are as follows:1)Obtain a three-dimensional model of the exhaust manifold product,and clean the surface of the model.First spray the exhaust manifold product with a developer,and then paste the marking points,and then use the optical scanner to scan to obtain the point cloud data model,and use the Geomagic Warp software to complete the point cloud data model processing.Using the processed point cloud data model,Geomagic Design X and UG software are used to complete the reconstruction of the exhaust manifold model.Through the 3D accuracy comparison of Geomagic Control X,a reasonable exhaust manifold reconstruction model is obtained.2)Obtain reasonable exhaust manifold thermal load analysis results.First build a one-dimensional engine model,compare simulation and test data to verify the effectiveness of the model.Obtain the optimal pipe diameter and obtain the required thermal boundary conditions of the exhaust manifold.The fluid-solid coupling method is adopted to obtain the temperature field,thermal stress and thermal deformation of the exhaust manifold.On the basis of this temperature,the thermal mode of the exhaust manifold is analyzed to obtain the vibration characteristics under the action of the temperature field,and the temperature field,thermal stress,thermal deformation and thermal mode of the exhaust manifold are analyzed.3)For the two project goals,complete the optimization and improvement of the exhaust manifold model,and perform the geothermal load analysis on the improved exhaust manifold model under the same boundary conditions.The thermal load analysis results show that the optimized and improved model meets the requirements and meets the product design standards,Can be used to solve practical engineering problems.