In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large...In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.展开更多
The effects of fire extinguishment with water mist by adding different additives were studied.Tens of chemical substances (including alkali metal salt,dilution agent and surface active agent) were selected as additive...The effects of fire extinguishment with water mist by adding different additives were studied.Tens of chemical substances (including alkali metal salt,dilution agent and surface active agent) were selected as additives due to their different extinct mechanisms.At first the performance of fire extinguishment with single additive was studied,then the effects of the same kinds of chemical substances under the same mass fraction were compared to study their influences on the fire extinguishment factors,including extinct time,fire temperature and oxygen concentration from which the fire extinct mechanism with additives could be concluded.Based on this the experiments were conducted to study the cooperate effect of the complexity of different additives.It indicated the relations between different firefighting mechanisms and different additives were competitive.From a large number of experiments the extinct mechanism with water mist by adding additives was concluded and an optimal compounding additive was selected.展开更多
基金Supported by the National Natural Science Foundation of China(No.61105086)Self-Planned Task(SKLRS-2010-MS-12)of State Key Laboratory of Robotics and System(HIT)Hubei Province Natural Science Foundation(No.2010CDB03405)
文摘In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.
基金supported by National Natural Science Foundation of China(No.51078014)supported by the Fundamental Research Funds for the Central Universities (YWF-10-01-B11)
文摘The effects of fire extinguishment with water mist by adding different additives were studied.Tens of chemical substances (including alkali metal salt,dilution agent and surface active agent) were selected as additives due to their different extinct mechanisms.At first the performance of fire extinguishment with single additive was studied,then the effects of the same kinds of chemical substances under the same mass fraction were compared to study their influences on the fire extinguishment factors,including extinct time,fire temperature and oxygen concentration from which the fire extinct mechanism with additives could be concluded.Based on this the experiments were conducted to study the cooperate effect of the complexity of different additives.It indicated the relations between different firefighting mechanisms and different additives were competitive.From a large number of experiments the extinct mechanism with water mist by adding additives was concluded and an optimal compounding additive was selected.
