New Generation Rocket Engines with Aerospike Nozzle
Specific needs of modern have led to complex technologies of the 21st-century and it is a well-known fact that applicable complex technology awaits its advanced specification revision. Recent research in aerodynamics and material science have highlighted more effective, compact, and reliable aerospike nozzle technology. New scientific developments put aerospike nozzle at the center of current space technologies. Aerospike Nozzle has high compatibility with Detonation Space’s (DS Inc.) ring-shaped combustor. With DS’s works, aerospike nozzle have ensured transfer theoretical studies to practice.
Aerospike Nozzles were not used in the first years due to technological deficiencies and lack of theoretical works. With the ring-shaped detonation combustors which have developed by Detonation Space Inc., made possible to use aerospike nozzle in LUNDET-7. LUNDET-7’s regenerative cooling system pushing the limits of efficiency and mobility with its compact aerospike nozzle and detonation engine. 7 kN thrust take place with %30 more specific impulse than conventional rocket engines.
The aerodynamic outputs of the DS Inc’s Aerospike Nozzle which is created by a the completely different nozzle geometry, create a superior effectiveness with respect to the bell nozzle technology. In a bell nozzle, combustion gases flow through a constriction (throat) and then the expansion away from the centerline is contained by the diverging walls of the nozzle up to the exit plane. Bells nozzles show optimum performance at one specific ambient pressure (i.e., altitude). It is difficult to achieve a desired performance of bellnozzles at high altitudes while also avoiding flow separation at the walls of the nozzle at low altitudes (during the launch). The latter can lead to structural failure of the nozzle. Therefore a compromise altitude must be used for the design point of a bell nozzle.
In a spike nozzle the opposite takes place — the gas flow is directed radially inward from an annulus at some diameter away from the centerline. This flow is directly exposed to ambient pressure and its expansion is thus directly coupled to the external environment (continuous altitude compensation with no moving parts). Thus, a very high area ratio nozzle (high vacuum performance) can also operate efficiently and safely at sea-level.
In these simulations, comparison of bell and aerospike shaped nozzles (0- 50 atm) was done in conditions where pressure is different but other all parameters such as tempreture, ambiant pressure, mesh number, fuel viscosite and thermodynemical parameters are constant.
According to ratios and mach numbers, efficiencies of nozzles and all other observations are listed in the chart. From the chart, ıt can be seen easily that aerospike nozzles are more effective than classic bell shaped nozlles under all different pressure ratios. Additionally, the rally between these shapes is going on at different altitudes.
Superior thermal characteristic of 625 series Inconel and Incoloy alloys define to DS Inc’s extended nozzle operation band. In addition to this broad band it’s compact geometry and working principle increase the variety of operative condition it can work with. This means it can be applied in many markets outside the space industry as a versatile technology.
Authors: Mechanical Eng. Ali Cem Bulut , Materials Eng. Ahmet Bugra Baser
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