ppt roket eng

8/10/2019 PPT ROKET ENG

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Nama Anggota

Albi Nuari H

Aji Prakoso

Sidiq Nuradiansyah

Yudha Bagus A


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Roket merupakan wahana luar angkasa, pelurukendali, atau kendaraan terbang yangmendapatkan dorongan melalui reaksi roket

terhadap keluarnya secara cepat bahan fluida darikeluaran mesin roket.
http://id.wikipedia.org/wiki/Peluru_kendalihttp://id.wikipedia.org/wiki/Peluru_kendalihttp://id.wikipedia.org/wiki/Mesin_rokethttp://id.wikipedia.org/wiki/Mesin_rokethttp://id.wikipedia.org/wiki/Peluru_kendalihttp://id.wikipedia.org/wiki/Peluru_kendali


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A solid rocket motor is a system that uses solidpropellants to produce thrust


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Solid rocket motors are used for

Launch vehicles

Ballistic Missiles


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Design involves: Analysis of combustion chamber environment

Stagnation temperature

Stagnation pressure

Propellant gases (material compatibility) Selection of insulation material

Material thickness determination for various areas ofthe motor case

For the cylindrical part of the case, the walls are onlyexposed to hot combustion gases at the end of theburn


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The design of the nozzle follows similarsteps as for other thermodynamic rockets Throat area determined by desired stagnation

pressure and thrust level

Expansion ratio determined by ambientpressure or pressure range to allow maximumefficiency

Major difference for solid propellantnozzles is the technique used for cooling

Ablation Fiber reinforced material used in and near the

nozzle throat (carbon, graphite, silica,phenolic)
http://images.google.com/imgres?imgurl=http://www.kerc.msk.ru/ipg/development/rd3.jpg&imgrefurl=http://www.kerc.msk.ru/ipg/development/srm.shtml&h=411&w=252&sz=12&tbnid=WP7hWectVZcIHM:&tbnh=121&tbnw=74&hl=en&start=7&prev=/images%3Fq%3Dsolid%2Bpropellant%2Bnozzle%26svnum%3D10%26hl%3Den%26lr%3D


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Meteorite Re-entry speed of 10 - 20 km/sec

Extreme heating in the atmosphere

Ablation and internal energy modes cooled themeteorite through its fall Ablation gas cloud

Dissociation

Internal energy deposition
http://www.dmsweb.org/


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Large solid motors typically use a three-stage

ignition system Initiator: Pyrotechnic element that converts electrical

impulse into a chemical reaction (primer)

Booster charge

Main charge: A charge (usually a small solid motor) thatignites the propellant grain. Burns for tenths of asecond with a mass flow about 1/10 of the initialpropellant grain mass flow.


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Two main catagories

Double Base: A homogeneous propellant grain,usually nitrocellulose dissolved in nitroglycerin.

Both ingredients are explosive and act as a combinedfuel, oxidizer and binder

Composite: A heterogeneous propellant grain withoxidizer crystals and powdered fuel held together ina matrix of synthetic rubber binder.

Less hazardous to manufacture and handle


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Fuel 5-22% Powdered Aluminum

Oxidizer 65-70% Ammonium Perchlorate (NH4ClO4 or AP)

Binder 8-14% Hydroxyl-Terminated

Polybutadiene (HTPB)


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Aluminum (Al) Molecular Weight: 26.98 kg/kmol

Density: 2700 kg/m3

Most commonly used Magnesium (Mg)

Molecular Weight: 24.32 kg/kmol

Density: 1750 kg/m3

Clean burning (green) Beryllium (Be)

Molecular Weight: 9.01 kg/kmol

Density: 2300 kg/m3

Most energetic, but extremely toxic exhaust products


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Ammonium Perchlorate (AP) Most commonly used

Cl combining with H can form HCl Toxic

Depletion of ozone

Ammonium Nitrate (AN) Next most commonly used

Less expensive than AP Less energetic

No hazardous exhaust products


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Hydroxyl Terminated Polybutadiene (HTPB)

Most commonly used

Consistency of tire rubber

Polybutadiene Acrylonitrile(PBAN)

Nitrocellulose (PNC)

Double base agent


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Used to promote

Curing

Enhanced burn rate (HMX)

Bonding

Reduced radiation through

the grain (darkening)

Satisfactory aging Reduced cracking


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Advantages High thrust

Simple

Storability

High density Isp

Disadvantages Low Isp (compared to liquids)

Complex throttling Difficult to stop and restart

Safety


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