Air standard efficiency is taken as
the ideal efficiency of an internal combustion engine
. … This would mean that whatever the temperature of the charge reached during combustion, the final temperature would have to be absolute zero. This implies that the exhaust gases would have to be -273′′С.
What is the air standard?
The air-standard cycle is an
idealized cycle
founded on the following approximations: (1) The working fluid throughout the cycle is only air; (2) the air acts as an ideal gas; (3) combustion processes are replaced by well-defined heat addition processes; and (4) the exhaust process is replaced by a heat rejection …
What do you mean by air standard cycle?
Air standard cycle is defined as
a reversible heat engine in which the source of heat supply and the sink for heat rejection are external to the air
. This cycle is a good approximation for many so-called internal combustion cycles.
What is air standard efficiency of Otto cycle?
The following data was observed for a CI engine: Fuel-air ratio: 0.04, Volumetric efficiency:
85%
, Indicated mean effective pressure: 8 bar, Fuel calorific value: 44000 kJ/kg, Density of air: 1 kg/m3.
Is air standard efficiency and thermal efficiency same?
Thermal efficiency relates to processes where the input is thermal energy as in a fired power plant, a internal combustion engine or solar energy systems. … It is the ratio of the mechanical output to the thermal input. Overall efficiency looks at entire systems from the initial input to the final output.
What is a standard efficiency?
Air standard efficiency is taken as
the ideal efficiency of an internal combustion engine
. … (a) No transfer of heat between the working surfaces and the air (b) Instantaneous and complete combustion (C) No change in volume during the combustion (constant volume) (d) Specific heat capacity is assumed to be constant.
Which cycle is more efficient?
Explanation:
Otto cycle
is more efficient than Diesel cycle for a given compression ratio. 6. For constant maximum pressure and heat input, the air standard efficiency of the gas power cycle is in the order.
What is an air standard analysis?
An air-standard study analysis is
used to study the open gas turbine engine with the assumptions that air is the working ideal gas and the energy generated by combustion is accomplished by a heat transfer source
. … The air-standard Brayton cycle consists of two heat exchangers, a compressor, and a turbine.
What are the air standard assumptions?
9-6C The air standard assumptions are: (1) the working fluid is air which behaves as an ideal gas, (2) all the processes are internally reversible, (3)
the combustion process is replaced by the heat addition process
, and (4) the exhaust process is replaced by the heat rejection process which returns the working fluid …
What is an air fuel cycle?
3-1: Fuel Air Cycle: theoretical cycle based on the actual properties of the cylinder contents is called the fuel – air cycle. The fuel – air cycle take into consideration the following: 1-
The actual composition of the cylinder contents
. 2- The variation in the specific heat of the gases in the cylinder.
Which has higher efficiency Otto or diesel?
3. 6 Diesel Cycle. … Although for a given compression ratio the
Otto cycle has higher efficiency
, because the Diesel engine can be operated to higher compression ratio, the engine can actually have higher efficiency than an Otto cycle when both are operated at compression ratios that might be achieved in practice.
What is K in Otto cycle?
Thermal Efficiency Derivation
A typical value for an air/fuel mixture is
k = 1.35
.
What is the efficiency of Carnot cycle?
It is well known that the Carnot cycle efficiency (
η thermal = 1 − T L T H
) is maximized with the highest possible heat source temperature T
H
and the lowest possible heat sink temperature T
L
.
What is the formula of thermal efficiency?
The thermal efficiency, η
th
, represents the fraction of heat, Q
H
, that is converted to work. The air-standard Otto cycle thermal efficiency is a function of compression ratio and
κ = c
p
/c
v
. The thermal efficiency, η
th
, represents the fraction of heat, Q
H
, that is converted to work.
What are the factors of thermal efficiency?
The thermal efficiency of a heat engine is expressed as a product of the Carnot efficiency,
the external irreversibility factor and the internal irreversibility factor
, by which the three factors that affect the thermal efficiency can be clearly distinguished, and the influences of the external and internal …
How can I improve the thermal efficiency of my house?
- Reduce your heating or use a secondary heating source.
- Use a new, energy efficient boiler.
- Fit insulation.
- Double or triple glazing.
- Draught proofing.
- Generate your own energy from renewable sources.
- Energy efficient fittings.
