Search results
Results from the WOW.Com Content Network
Specific impulse should not be confused with energy efficiency, which can decrease as specific impulse increases, since propulsion systems that give high specific impulse require high energy to do so. [3] Specific impulse should not be confused with total thrust. Thrust is the force supplied by the engine and depends on the propellant mass flow ...
Using liquid methane and liquid oxygen as propellants is sometimes called methalox propulsion. [19] Liquid methane has a lower specific impulse than liquid hydrogen, but is easier to store due to its higher boiling point and density, as well as its lack of hydrogen embrittlement. It also leaves less residue in the engines compared to kerosene ...
A liquid-propellant rocket or liquid rocket uses a rocket engine burning liquid propellants. (Alternate approaches use gaseous or solid propellants.) Liquids are desirable propellants because they have reasonably high density and their combustion products have high specific impulse (I sp). This allows the volume of the propellant tanks to be ...
Solid fuel rockets have lower specific impulse, a measure of propellant efficiency, than liquid fuel rockets. As a result, the overall performance of solid upper stages is less than liquid stages even though the solid mass ratios are usually in the .91 to .93 range, as good as or better than most liquid propellant upper stages.
Cryogenic or volatile propellants generally do not need a separate pressurant; instead, some propellant is expanded (often with engine heat) into low-density gas and routed back to its tank. A few highly volatile propellant designs do not even need the gas loop; some of the liquid automatically vaporizes to fill its own container.
Storing liquid propellant may pose attitude control issues due to the sloshing of fuel in its tank. When choosing a propellant, a high specific impulse, and a high specific impulse per unit volume of propellant should be considered. [3] Overview of the specific impulses of propellants suitable for a cold gas propulsion system:
Liquid propellants provide greater propulsive thrust and power, but require more complex technology and extra weight. Solid fuel is dense and burns quite quickly, generating thrust over a short time.
Specific impulse (usually abbreviated I sp) is a measure of how effectively a rocket uses propellant or jet engine uses fuel. By definition, it is the total impulse (or change in momentum) delivered per unit of propellant consumed [4] and is dimensionally equivalent to the generated thrust divided by the propellant mass flow rate or weight flow rate. [5]