F1technical.net

Monza has the highest full throttle percentage at around 70-75%.

Brian Coat wrote:In RET this month Rob White was asked if MGU-H power is about 90kW: "You are in the ball park and have the right number of zeroes" or words to that effect.

Gnomic as usual but implies < 100 kW?

Probably no shock given you'd only need 120 kW in order to run round at full load with no braking!

RET? do you have the whole interivew?

At (say) 75% residence time @ full load, and 2000 MJ/lap KERS harvest limit, a first order approximation of maximum self sustaining MGU-H power is easy enough to estimate (but a first order approximation doth not a race winning F1 design make, so this is an important figure).

Of course we need to remember that the only source of *unrestricted power* for the wheels is actually the ICE ... If you see whatI mean ...

Of course Monza is not great for MGU-K harvesting. Basic calculations I made a while ago suggest just over half the harvesting limit per lap.

Right, the 2MJ is just an upper limit.

Your estimate makes sense for a circuit like that.

Tommy Cookers wrote:there is no such mechanism
there is a mechanism that transforms some of the exhaust pressure or velocity into electrical energy

There is... I think your concept of heat is why you say that. Heat is the transfer of internal energy. That heat is used to expand the gas as it flows through the turbine. A portion of the energy sued to turn the turbine is impulse (from the momentum change of the gases) and the other portion is from what we call "reaction" which is energy that comes from the gas expanding due to it's heat content as the pressure drops across the turbine. There is even something that is called "Blade-reheat" which is actually the friction from the turbine blades reheating the gases - this has even been shown to add a litle more efficieny. There are even some people who inject fuel into the exhaust (anti-lag?) in an effort to spin the turbines faster. Heat is very important to a turbine. A turbine is very much a device that absorbs heat. The temperature drop of a turbine is significant. Just preventing you from spreading more misinformation.

so, as a result of the exhaust gasses expanding when they exit that tight volute (turbine inlet) there is a temperature drop, 100deg c maybe ?
i,m guessing the exhaust gasflow is the main driving force for the compressor tho ?

Yeah, heat is important. That is why the exhaust is insulated. The more a turbine can expand the gas going through it the more energy it can take from the gas. The hotter the gas is the more it will expand as it leaves the turbine and the more energy you can get from the gas due to pressure difference.

Frank_ wrote:so, as a result of the exhaust gasses expanding when they exit that tight volute (turbine inlet) there is a temperature drop, 100deg c maybe ?

About 250 *C.

PlatinumZealot wrote:

Tommy Cookers wrote:there is no such mechanism
there is a mechanism that transforms some of the exhaust pressure or velocity into electrical energy

There is... I think your concept of heat is why you say that. Heat is the transfer of internal energy. That heat is used to expand the gas as it flows through the turbine. A portion of the energy sued to turn the turbine is impulse (from the momentum change of the gases) and the other portion is from what we call "reaction" which is energy that comes from the gas expanding due to it's heat content as the pressure drops across the turbine. There is even something that is called "Blade-reheat" which is actually the friction from the turbine blades reheating the gases - this has even been shown to add a litle more efficieny. There are even some people who inject fuel into the exhaust (anti-lag?) in an effort to spin the turbines faster. Heat is very important to a turbine. A turbine is very much a device that absorbs heat. The temperature drop of a turbine is significant. Just preventing you from spreading more misinformation.

@ PZ
99.8% of the population has the same concept of heat that you seem to imagine I have
including those receiving in the UK the elementary science education that is compulsory and, importantly, those providing it
these people were asking about the nature of the FIA's apparent powerful innovation in turning heat into electricity

sincerely, please explain what happens and why .....
with a turbine/generator in a duct when a temporary gas barrier initially positioned across the turbine is removed ....
1. starting with hot air at ambient pressure 'upstream'
2. starting with ambient temperature air at high pressure 'upstream'

I suggest that science should have been more careful about adopting an everyday term and sometimes using it for special purpose
I have posted against Joe Public's use of purpose-made science and engineering terms for and wrongly in everyday applications
without being accused of misinforming
and yes, I have heard of enthalpy etc

again, sincerely, please explain the above 2 cases
Joe Public might well be interested

You are talking about a gas that is already flowing through the turbine? Or an initially stagnant gas? Tell me so I can illustrate for you if you don't understand. I am always happy to explain these things. No problem.

PlatinumZealot wrote:

Tommy Cookers wrote:there is no such mechanism
there is a mechanism that transforms some of the exhaust pressure or velocity into electrical energy

There is... I think your concept of heat is why you say that. Heat is the transfer of internal energy. That heat is used to expand the gas as it flows through the turbine. A portion of the energy sued to turn the turbine is impulse (from the momentum change of the gases) and the other portion is from what we call "reaction" which is energy that comes from the gas expanding due to it's heat content as the pressure drops across the turbine. There is even something that is called "Blade-reheat" which is actually the friction from the turbine blades reheating the gases - this has even been shown to add a litle more efficieny. There are even some people who inject fuel into the exhaust (anti-lag?) in an effort to spin the turbines faster. Heat is very important to a turbine. A turbine is very much a device that absorbs heat. The temperature drop of a turbine is significant. Just preventing you from spreading more misinformation.

You are both right. There is one mechanism that transforms some of the heat energy in the exhaust into exhaust pressure and/or velocity. (Called isentropic expansion). There is a second mechanism that transforms some of the exhaust pressure or velocity into electrical energy. (Called a turbine + MGUH)

PlatinumZealot wrote:You are talking about a gas that is already flowing through the turbine? Or an initially stagnant gas? Tell me so I can illustrate for you if you don't understand. I am always happy to explain these things. No problem.

Ambient pressure means 1bar absolute.

gruntguru wrote: You are both right. There is one mechanism that transforms some of the heat energy in the exhaust into exhaust pressure and/or velocity. (Called isentropic expansion). There is a second mechanism that transforms some of the exhaust pressure or velocity into electrical energy. (Called a turbine + MGUH)

that makes a lot of sense gruntguru
with regards to power consumption of the actual compressor tho (did you state 100kw somewhere ?) most turbo,s connecting shafts are only 5 or 6mm dia, so how can a 400hp disco potato 6mm shaft transmit so much power through it ? (albeit @ 150k rpm)

Frank_ wrote:

gruntguru wrote: You are both right. There is one mechanism that transforms some of the heat energy in the exhaust into exhaust pressure and/or velocity. (Called isentropic expansion). There is a second mechanism that transforms some of the exhaust pressure or velocity into electrical energy. (Called a turbine + MGUH)

that makes a lot of sense gruntguru
with regards to power consumption of the actual compressor tho (did you state 100kw somewhere ?) most turbo,s connecting shafts are only 5 or 6mm dia, so how can a 400hp disco potato 6mm shaft transmit so much power through it ? (albeit @ 150k rpm)

I think you have answered your own question. At 125k rpm (F1 limit for MGUH), 8 Nm of torque gives 105 kW.