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THE Laws of Thermodynamics Thread (merged)

General discussions of the systemic, societal and civilisational effects of depletion.

Re: THE Laws of Thermodynamics Thread (merged)

Unread postby kublikhan » Sat 24 Aug 2019, 18:51:11

CALORIFIC VALUES OF VARIOUS WASTE TYPES
Material kcal/kg
Rubber 5600
Neoprene 7100
Car tires 8300
Oil sludge 8800
Paraffin 10340
Polyethylene 10990
Polypropylene 11030
Calorific Content

What is the caloric content of a litre of rocket fuel?
It depends on the choice of rocket fuel. The two most common rocket fuels are cryogenic liquid Hydrogen (LH2) and refined kerosene (RP-1). LH2 is what powered the Space Shuttle Main Engines, the cluster of three engines on the orbiter itself. RP-1 is the fuel that powered the first stage of the Saturn V, the rocket that took people to the Moon, as well as Russia's Soyuz, and SpaceX's Falcon 9. Liquid Hydrogen has 2256.2 Kcals (1 Kcal is a food calorie) per litre and Kerosene has 8938.8 Kcal per litre. Kerosene is used in lower stages of rockets because it is much denser than Hydrogen and provides more thrust, but is much less efficient because of the high molecular weight of the exhaust. Hydrogen is used in upper stages of rockets where density isn't as much of an issue but efficiency becomes more important. A good guide to understanding it easier is that Hydrogen has more energy per kilo while Kerosene has more energy per litre.

What is the caloric content of a litre of rocket fuel?


Code: Select all
Table of calorific value of fuels
Fuel          Calorific value
Hydrogen      150 KJ/g
Methane        55 KJ/g
LPG            50 KJ/g
Kerosene oil   48 KJ/g
CALORIFIC VALUE OF FUELS

Abstract
The classic hybrid rocket which employs hydroxylterminated polybutadiene (HTPB) fuel is characterized by low ablation rate. To enhance the ablation rate, paraffin was added to the HTPB.

The combustion enthalpy of HTPB blended with paraffin is determined by oxygen bomb calorimeter at a constant volume. The standard combustion enthalpy of pure HTPB and paraffin was found to be 37.9 and 41.9MJ kg−1.
Study of Thermo-Mechanical Properties of HTPB–Paraffin Solid Fuel

Combining some of the above values and converting them into the same units I get(assuming I didn't screw this up):
Code: Select all
Table of calorific value of fuels
Fuel          Calorific value
Hydrogen      150 KJ/g
Kerosene oil   48 KJ/g
Paraffin       43 KJ/g
HTPB           38 KJ/g
Car tires      35 KJ/g
Neoprene       30 KJ/g
Rubber         23 KJ/g
The oil barrel is half-full.
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Re: THE Laws of Thermodynamics Thread (merged)

Unread postby Tanada » Mon 26 Aug 2019, 13:07:53

kublikhan wrote:
CALORIFIC VALUES OF VARIOUS WASTE TYPES
Material kcal/kg
Rubber 5600
Neoprene 7100
Car tires 8300
Oil sludge 8800
Paraffin 10340
Polyethylene 10990
Polypropylene 11030
Calorific Content

What is the caloric content of a litre of rocket fuel?
It depends on the choice of rocket fuel. The two most common rocket fuels are cryogenic liquid Hydrogen (LH2) and refined kerosene (RP-1). LH2 is what powered the Space Shuttle Main Engines, the cluster of three engines on the orbiter itself. RP-1 is the fuel that powered the first stage of the Saturn V, the rocket that took people to the Moon, as well as Russia's Soyuz, and SpaceX's Falcon 9. Liquid Hydrogen has 2256.2 Kcals (1 Kcal is a food calorie) per litre and Kerosene has 8938.8 Kcal per litre. Kerosene is used in lower stages of rockets because it is much denser than Hydrogen and provides more thrust, but is much less efficient because of the high molecular weight of the exhaust. Hydrogen is used in upper stages of rockets where density isn't as much of an issue but efficiency becomes more important. A good guide to understanding it easier is that Hydrogen has more energy per kilo while Kerosene has more energy per litre.

What is the caloric content of a litre of rocket fuel?


Code: Select all
Table of calorific value of fuels
Fuel          Calorific value
Hydrogen      150 KJ/g
Methane        55 KJ/g
LPG            50 KJ/g
Kerosene oil   48 KJ/g
CALORIFIC VALUE OF FUELS

Abstract
The classic hybrid rocket which employs hydroxylterminated polybutadiene (HTPB) fuel is characterized by low ablation rate. To enhance the ablation rate, paraffin was added to the HTPB.

The combustion enthalpy of HTPB blended with paraffin is determined by oxygen bomb calorimeter at a constant volume. The standard combustion enthalpy of pure HTPB and paraffin was found to be 37.9 and 41.9MJ kg−1.
Study of Thermo-Mechanical Properties of HTPB–Paraffin Solid Fuel

Combining some of the above values and converting them into the same units I get(assuming I didn't screw this up):
Code: Select all
Table of calorific value of fuels
Fuel          Calorific value
Hydrogen      150 KJ/g
Kerosene oil   48 KJ/g
Paraffin       43 KJ/g
HTPB           38 KJ/g
Car tires      35 KJ/g
Neoprene       30 KJ/g
Rubber         23 KJ/g


Thank You! That is exactly what I was searching for! For those whose curiosity was piqued by the search, The UK/EU adopted an air to air missile system over a decade ago that operates by launching as a conventional solid rocket motor (The HTPB phase) then it switches to an air breathing solid fuel phase most reporters are calling "Solid Fueled Ramjet" as a sustainer rocket phase to create a very long range fuel supply compared to traditional HTPB fuel. The argument I got into elsewhere was about whether a Kerosene fueled ramjet was more efficient on a weight for range calculation than the new air breathing solid fuel versions being adopted world wide. The UK adopted the system in 2016 and since then China, Russia and now India as well are producing their own versions of these "Solid Fuel Ramjets" so clearly the military's outside of the USA have found that these things have merit. In a replay of the "Not Invented Here" syndrome so far the US DOD has not been willing to either develop our own or license the UK design for our military defense needs.

Based on the data you provided above Kerosene has a larger energy density which is mildly surprising. It seems like the easy storability and simplicity of the "Solid Fuel Ramjets" must be the determining factor as in the past many American missiles were launched via solid rocket motor and then switched to kerosene fueled ramjet sustainer engines for the majority of their flight path. However despite its higher energy a kerosene fueled ramjet requires a pump and a few fuel feed and flame holder parts the same as any other jet engine. Going to solid fuel eliminates the need for that as the fuel only burns on the exposed surface and is hard enough to maintain its shape while the incoming air feeds the combustion process.
I should be able to change a diaper, plan an invasion, butcher a hog, design a building, write, balance accounts, build a wall, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, pitch manure, program a computer, cook, fight efficiently, die gallantly. Specialization is for insects.
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Re: THE Laws of Thermodynamics Thread (merged)

Unread postby Newfie » Mon 26 Aug 2019, 18:22:41

Interesting stuff. Thanks guys.
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Re: THE Laws of Thermodynamics Thread (merged)

Unread postby GHung » Tue 27 Aug 2019, 20:54:58

This thread had newer posts. What happened?
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Re: THE Laws of Thermodynamics Thread (merged)

Unread postby kublikhan » Wed 28 Aug 2019, 03:21:18

GHung wrote:This thread had newer posts. What happened?
I believe they were moved to the SpaceX thread.
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