Research On The Device Testing The Flow Characteristics Of Nozzles In Carbon Dioxide Extinguishing Systems

In carbon dioxide automatic fire extinguishing systems, nozzles are the most important parts with the largest amount being used. When nozzles spray, their flow characteristics play a great role to the extinguishing effect and the safety of extinguishing systems. Therefore, it is very important to set up a device testing the flow characteristics of nozzles in carbon dioxide extinguishing systems for testing, inspecting and researching the flow characteristics of nozzles. It is also significant for the quality supervision to this kind of products.This paper introduces the specialties of carbon dioxide extinguishing agent and extinguishing systems, analyzes and summarizes the structure and the flow characteristics of nozzles. It introduces the process of researching and designing the device testing the flow characteristic of nozzles in carbon dioxide extinguishing systems according to the stipulation about performance requirements and test methods for nozzles of carbon dioxide extinguishing systems in the national standard GB 16669-1996 (General technical specifications for components of carbon dioxide fire extinguishing systems). It describes in detail about the design principle of the test device, the designing of pipes, brackets and pipe hangers, the selection and installation of sensors, error of measurement, the design principle of data collection and programming principle of process software, and the debugging of the whole device.Using this test device, during the period of carbon dioxide spraying, data such as the mass of sprayed carbon dioxide in unit time and the pressures at the inlets of nozzles can be gathered and recorded at the real time through loading sensors and pressure sensors by computers. Then the flow characteristics of nozzles (mass flow in unit area under different pressures) can be figured out. Basing on the data analyses, flow characteristic curves of nozzles can be plotted, and the relevant data can be printed and saved.The probation of the device testing the flow characteristics of nozzles in carbon dioxide extinguishing systems shows a reasonable design, a reliable method and a stable performance. It is easy to operate the device, and its general technical property is able to meet the requirements of practical design computation in engineering. The test method adopted is not only suitable for the spray process with gas-liquid two phases fluid, but also suitable for that with one phase situation, so as to avoid complex analyses and computations of flow characteristics and thermodynamics, etc.