2022 Fiscal Year Final Research Report
Clarification of Extinguishing Mechanism of Airburst Blast Extinguishment
| Project/Area Number |
20H02393
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 25020:Safety engineering-related
|
|---|
| Research Institution | Hirosaki University |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2020-04-01 – 2023-03-31
|
| Keywords | 爆風消火 / 爆薬 / 空中起爆 / ブラスト波 / 反射ブラスト波 / 火災 / 拡散火炎 / 消炎 |
|---|
| Outline of Final Research Achievements |
Basic research on airburst blast extinguishment using micro explosives has been carried out, and it is clarified that the formation of reflected blast waves on the ground increases the extinguishing effectiveness of the blast extinguishment. In particular, the horizontal distance between the jet diffusion flame and the location of airburst shows the geatest when Mach reflection occurs. The horizontal distance of the effective range of the blast extinguishment, within which the diffusion flame can be always blown off by the blast waves, is organized by Sach's scaling law. Therefore, using this relationship, it is found that the experimental results of airburt blast extinguishing obtained on a laboratory scale can be applied to actual-scale blast extinguishment. These research results have greatly improved the applicability of airburst blast extinguishment using explosives as an emergency firefighting method for large-scale forest fires and earthquake fires.
|
| Free Research Field |
消火の科学・技術
|
| Academic Significance and Societal Importance of the Research Achievements |
地震火災や大規模林野火災に対する緊急の消火法として爆風消火は使用することができる．そこで微小爆薬を用いて空中起爆爆風消火の消火機構を解明する基礎研究を行った．空中起爆を行うと，ブラスト波が地面で反射して反射ブラスト波が形成される．起爆高さによって先行するブラスト波と反射したブラスト波が重なるマッハ反射が生じる．このマッハ反射が生じて拡散火炎と干渉する条件で，爆風消火によって消火できる爆点と拡散火炎との距離が最も大きくなることが分かった．このようにマッハ反射が生じて爆風が火炎に作用する爆点高さが，空中起爆爆風消火における最適起爆点高さであることを明らかにした．
|
