The Design And Research On A Gas-water Mix-type Marine Fire Hydrant

The characteristics of ships fire include the fire point hiding, difficult to discover, the room is narrow and small, the explosion hazard is high, easy to cause the personnel casualty, to rescue difficultly, the convection conducts rapidly, easy to spread and so on. So it is very important to equip effective fire-extinguishing plants. The existing fire-extinguishing plants have a lot of problems. For example, the amount of extinguishant is very large, mix is uneven, extinguishant is easy to splash, harmful to the human, the system structure is complex, spray nozzle is demanding and so on. And the open literature sources on the marine fire hydrant are very few. Besides, because of the difficulty of numerical simulation of two-phase flow, the research on numerical simulation of the marine fire hydrant is hardly any. In this thesis, a new-style marine fire hydrant is designed to be small volume, easy to use and low pressure lost. It blends the gas to water through its special structure. It regards the gas-water mixture as the extinguishant. In this way, the water flow can be soften, and reduce the splash. The extinguishant can overlay the burnable body uniformly. At last, reach the better extinguishment under the dual effect of the oxygen exclusion and cooling.This thesis will study and design the device on both numerical simulation and experiments. The main work is as follows:1. Through the research on the problems of the existing marine fire extinguisher, the paper designs a gas-water mixed fire hydrant which can match to the fire hose. And use the single-phase flow numerical simulation to reduce the total pressure loss.2. It establishes different types of the pump nozzle models and calculates with the VOF steady model. Select the best effective device model. Do some research on the selected model under different conditions. Then use different computational methods to study the same model and compare with the VOF steady model. And this provides a theoretical basis guiding for the experiment.3. Do the experimental study with the air being the gaseous extinguishant. And the fire extinguisher is validated and amended. Combining the numerical simulation, the effective fire extinguisher is designed. And this verifies the correctness of the result of numerical simulation. 4. This paper proposes a method to raise the efficiency of the extinguishment, which regard the carbon dioxide as the gaseous extinguishant. And base on numerical simulation, it validates that the fire extinguisher is adapt to mix carbon dioxide and water.