The Turbulent-Laminar Transition on the Rocket Surface During the Injection
| Autor: | Ivan Karakotin, Irina Yurchenko, Alexander Kudinov |
|---|---|
| Jazyk: | ruština |
| Rok vydání: | 2014 |
| Předmět: |
Surface (mathematics)
business.product_category Materials science lcsh:Computer engineering. Computer hardware Turbulence Laminar flow lcsh:TK7885-7895 General Medicine Mechanics boundary layer transition criterion heat exchange Physics::Fluid Dynamics Rocket calorimeter turbulent-laminar transition business lcsh:Mechanics of engineering. Applied mechanics lcsh:TA349-359 |
| Zdroj: | Nauka i Obrazovanie, Vol 0, Iss 9, Pp 88-105 (2014) |
| ISSN: | 1994-0408 |
| Popis: | The variety of turbulent-laminar transition criteria in such environments as the launch vehicle injection points to the essential influence of spherical nose roughness, which is included in one form or another in the critical Reynolds numbers for a lot of explorers of blunt bodies. Some of researchers of the reentry bodies have founded the correlation functions between the momentum thickness Reynolds number and Max number as the transition criteria.In this article we have considered results of flight tests carried out using launch vehicles to define boundary layer regime on the payload fairing surface. The measurements were carried out using specially designed complex of gages consisted of calorimeters, surface temperature gages, and pressure gages. The turbulent-laminar transition was defined in accordance with the sharp change of calorimeter readings and flow separation pressure gages indication.The universal criterion of turbulent-laminar transition has been identified for blunted payload fairings i.e. Reynolds number Reek based on the boundary layer edge parameters in the sonic point of the payload fairing spherical nose and surface roughness height k, which gives the best correlation of all data of flight experiment conducted to define turbulent-laminar transition in boundary layer. The criterion allows defining time margins when boundary layer regime is turbulent at Reek=20±14 existing on space head surfaces and at Reek=6±5 the boundary layer regime is totally laminar.It was defined that under conditions when there are jointly high background disturbances of free stream flux at operation of main launch vehicle engines and influence of the surface roughness the critical value of Reynolds number is an order-diminished value as compared to the values obtained in wind tunnels and in free flight.It was found that with decreasing of roughness influence in growing boundary layer the flow disturbances evolution wide apart the payload fairing nose along the surface rocket stages is close to the turbulization mechanism at the smooth surfaces. The criterion of transition from transient to turbulent regime at the surface rocket is momentum thickness Reynolds number Reθ = 900±100. The criterion of transition absence and the laminar boundary layer regime on the steps surface is Reθ = 200±50. |
| Databáze: | OpenAIRE |
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