Numerical simulation for flow and heat transfer of side exhaust spray of marine diesel engines

  Objectives  In order to solve the problem of evaluating the cooling performance of the side exhaust spray devices for marine diesel engines,

  Methods  the Mixture multiphase flow model and evaporation-condensation model were coupled to simulate the flow and heat transfer process of spray in the exhaust pipe numerically. The distribution of exhaust temperature field, the variation of average sectional temperature along the exhaust pipe and the pressure loss under different cooling water flow ratio were obtained and analyzed.

  Results  The simulation results show that, under spraying conditions, the high temperature zone in the exhaust pipe is conical due to the compressing of water as well as the gas-water mass and heat transfer. With the increase of the cooling flow rate ξ, the range of the high temperature zone is gradually narrowed. Along the exhaust pipe, the exhaust mixing temperature drops sharply from the dimensionless downstream distance χ=0.1 to χ=0.4, and afterwards, the temperature change slows down. The relationship between the total pressure loss and the cooling water flow rate is non-monotonic, and the influence on the exhaust resistance is small.

  Conclusions  The results can provide quantitative support for the optical design of the side exhaust spray devices.