Table of Contents
What is true about the difference between a bell nozzle and an aerospike?
In a bell nozzle, the exit pressure of the working gases are fixed by the nozzle geometry. With an aerospike nozzle, since there is no hard outer surface in which the gases expand, the gas expansion varies to match the current atmospheric pressure at all altitudes.
Why are aerospike engines not used?
In aerospike the pressure (and temperature) of the gas remains very high all along the spike surface, and the sharp tip leaves very little room for cooling systems. You have a lot of extra-hot, very dense gas in contact with the narrow spike that must pass all the coolant and dissipate the heat somehow, not to melt.
What are aerospike engines used for?
The aerospike engine is a type of rocket engine that maintains its aerodynamic efficiency across a wide range of altitudes. Aerospike engines have been studied for several years and are the baseline engines for many single-stage-to-orbit (SSTO) designs and were also a strong contender for the Space Shuttle main engine.
Are aerospike better than Bell nozzle?
Advantages and Disadvantages of Using an Aerospike Nozzle: The aerospike nozzle has 90\% overall better performance than the conventional bell shaped nozzle. The efficiency at low altitudes is much higher because the atmospheric pressure restricts the expansion of the exhaust gas.
What engine is more efficient *?
“Diesel engines are more fuel-efficient and have more low-end torque than similar-sized gasoline engines, and diesel fuel contains roughly 10\% to 15\% more energy than gasoline. So, diesel vehicles can often go about 20\% to 35\% farther on a gallon of fuel than their gasoline counterparts.
What is the most effective engine?
Fuel efficiency The new Wärtsilä 31 is the most fuel-efficient four-stroke engine currently available on the market. The diesel version of the engine consumes on average 8–10g/kWh less fuel compared with the closest competitor across its entire load range. At its optimum point this number can go as low as 165g/kWh.
Is any engine 100\% efficient?
It is impossible for heat engines to achieve 100\% thermal efficiency () according to the Second law of thermodynamics. This is impossible because some waste heat is always produced produced in a heat engine, shown in Figure 1 by the term.
What is the difference between bell nozzle and aerospike nozzle?
In a bell nozzle, the exit pressure of the working gases are fixed by the nozzle geometry. With an aerospike nozzle, since there is no hard outer surface in which the gases expand, the gas expansion varies to match the current atmospheric pressure at all altitudes. Therefore, the performance is optimal for all altitudes of the nozzle flight.
What is an aerospike engine?
Briefly, a spike (or “plug”) engine uses an exhaust nozzle that can be thought of as a conventional bell shaped nozzle turned inside-out. The aerospike nozzle is a truncated version of an ideal spike.
How does the aerospike nozzle constrain the exhaust plume?
The air flow around the aerospike nozzle exhaust is not what constrains the plume but rather the ambient pressure. Therefore, whether or not the nozzle is moving, the exhaust plume will be more or less the same (shear layer effects between the nozzle exhaust and the quiescent air being neglected, of course).
What is the advantage of bell nozzle?
The bell, the most commonly used nozzle shape, offers significant advantages over the conical nozzle, both in size and performance. Referring to the above figure, note that the bell consists of two sections. Near the throat, the nozzle diverges at a relatively large angle but the degree of diveregence tapers off further downstream.