Gas is compressed from (1) 1 bar 30 0C to (2) 5 bar 30 0C
Temp is constant. Hence process is isothermal. P x V = Constant
Description : Represent constant volume process on PV & TS diagram for steam.
Last Answer : Represent constant volume process on PV & TS diagram for steam.
Description : Assuming compression is according to the Law PV = C, Calculate the initial volume of the gas at a pressure of 2 bars w/c will occupy a volume of 6m³ when it is compressed to a pressure of 42 Bars. a) 130m³ b) 136m³ c) 120m³ d) 126m³ Formula: P1V1/T1 =P2V2/T2
Last Answer : 126m³
Description : The characteristic equation of gases pv = mRT holds good for (a) mono atomic gases (b) diatomic gases (c)real gases (d) ideal gases
Last Answer : Ans: c
Description : In diesel engine the fuel injected would burn instantaneously at about compressed air temperature of A. 1000°C B. 250°C C. 450°C D. 2000°C
Last Answer : ANSWER : A
Description : Which of the following is compressed in a diesel engine cylinder A. air B. fuel C. air and fuel D. air and lub oil
Description : Which of the following medium is compressed in a diesel engine cylinder? a. air b. air and fuel c. air and lubricating oil d. fuel
Last Answer : ANSWER a. air
Description : Allowable pressure on high-pressure side or ammonia absorption system is of the order of (a) atmospheric pressure (b) slightly above atmospheric pressure (c) 2-4 bars (d) 5-6 bars
Last Answer : Ans: d
Description : Represent generation of steam on H-S diagram. Show constant dryness fraction lines, constant temperature lines, saturated line and superheated region on the same.
Last Answer : Represent generation of steam on H-S diagram. Show constant dryness fraction lines, constant temperature lines, saturated line and superheated region on the same.
Description : In a constant pressure process steam is generated from 10 bar and 0.8 dry condition till it become dry and saturated. Determine amount of heat added per kg of steam. From steam table at 10 bar Tsat = 179.9°C hf = 762.6 kl/kg, hg = 2776.2 kJ/kg
Last Answer : Constant pressure process Final condition of steam is dry saturated Enthalpy of dry steam = hg= hf + hfg =2776.2 KJ/Kg .Given Latent heat of vaporization = hfg = hg - hf =2776.2-762.6 =2013.6 KJ/Kg Initial condition ... hfg = 762.6+0.8 X 2013.6 =2373.48 KJ/Kg Heat added = hg-hw = 402.72 KJ/kg
Description : In a two stage reciprocating air compressor, the suction and delivery pressure are 1 and 4 bar respectively. For maximum efficiency the intercooler pressure is A. 1.5 bar B. 2 bar C. 2.5 bar D. 3 bar
Last Answer : ANSWER : B
Description : Common rail injection system uses injection pressures of the order a) 100-200 bar b) 200-400 bar c) 400-600 bar d) 1500 bar
Last Answer : Answer: d Explanation: Generally, common rail injection system uses injection pressures of the order 1500 bar.
Description : The maximum delivery pressure in a rotary air compressor is A. 10 bar B. 20 bar C. 30 bar D. 50 bar
Description : In a four stage compressor, if the pressure at the first and third stage are 1 bar and 16 bar, then the delivery pressure at the fourth stage will be A. 1 bar B. 16 bar C. 64 bar D. 256 bar
Last Answer : ANSWER : C
Description : In a two stage reciprocating air compressor with a suction pressure of 2 bar and delivery pressure of 8 bar the ideal intercooler pressure will be A. 10 bar B. 6 bar C. 4 bar D. 3 bar
Description : An ideal gas is heated at constant volume and then expanded isothermally. Show processes on P-V & T-S diagrams.
Last Answer : Process 1-2 : Constant volume process Process 2-3 : Constant temperature process (Isothermal process)
Description : On the pressure-enthalpy diagram, condensation and de-superheating is represented by a horizontal line because theprocess (a) takes place at constant pressure (b) takes place at constant temperature (c) takes place at constant entropy (d) takes place at constant enthalpy
Last Answer : Ans: a
Description : The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents (a) condensation of the refrigerant vapour (b) evaporation of the refrigerant liquid (c) compression of the refrigerant vapour (d) metering of the refrigerant liquid
Last Answer : Ans: b
Description : Ratio of actual indicated work to hypothetical indicated work in a steam engine is the (a) Indicated thermal efficiency (b) Friction factor (c) Mechanical efficiency (d) Diagram factor
Last Answer : Ans : d
Description : The area of actual indicator diagram on an air compressor as compared to area of ideal indicator diagram is A. Less B. More C. Same D. Unpredictable
Description : Identify modes of heat transfer involved applications with brief explanation. (1) Radiator of automobile (2) Condenser of domestic refrigerator.
Last Answer : Modes of heat transfer Automobile radiator-A radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through ... of heat transfer plays very important deciding factor transferring heat from condenser tube to atmosphere.
Description : Vertical lines on pressure-enthalpy chart show constant (a) pressure lines (b) temperature lines (c) total heat lines (d) entropy lines
Description : Short horizontal lines on pressure-enthalpy chart show (a) constant pressure lines (b) constant temperature lines (c) constant total heat lines (d) constant entropy lines
Description : Explain the necessity of multi-staging and inter cooling in case of two stage compressor with PV diagram
Last Answer : Necessity of multi staging with intercooling in air compression: The large pressure ratio gives rise in high compression ratio and high discharged temperature which produce adverse effect on the efficiency and ... and saving in work and power multi staging with intercooling is necessary.
Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) gas liquefaction (c)commercial refrigerators (d) Chillers
Description : Condensing temperature in a refrigerator is the temperature (a) of cooling medium (b) of freezing zone (c) of evaporator (d) at which refrigerant gas becomes liquid
Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) commercial refrigerators (c) air conditioning (d) gas liquefaction
Description : Critical temperature is' the temperature above which (a) a gas will never liquefy (b) a gas will immediately liquefy (c) water will evaporate (d) water will never evaporate
Description : Critical pressure of a liquid is the pressure (a) above which liquid will remain liquid (b) above which liquid becomes gas (c) above which liquid becomes vapour (d) above which liquid becomes solid
Description : Supercharging is essential in A. aircraft engines B. petrol engines C. gas turbines D. diesel engines
Description : Whencrudeoilisheated, which of thefollowinghydrocarbonisgiven off first A. kerosene C. gasolene C. natural gas D. paraffin
Description : The energy of expanding gas is transferred by piston to connecting rod through a. Crank pin b. Gudgeon pin c. Bearing d. Crankcase (Ans:b)
Last Answer : Which of the following is not used in four stroke compression-ignition (CI) engines? a. Fuel pump b. Spark plug c. Fuel injector d. Inlet and outlet Valves (Ans:b)
Description : The _____________ sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: d Explanation: The air inlet temperature sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength whereas the engine temperature sensor senses the ... gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.
Description : The _____________ sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: c Explanation: The air flow sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel while exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.
Description : The _____________ sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: a Explanation: The engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting while the ... gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.
Description : In _____________ sensor, output voltage changes in proportion to air-fuel ratio. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: b Explanation: Only in exhaust gas sensor, output voltage changes in proportion to air-fuel ratio.
Description : _____________ senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio. a) Engine temperature b) Exhaust gas c) Air flow d) Air inlet temperature
Last Answer : Answer: b Explanation: Exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates airfuel ratio while engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting.
Description : Octane of natural gas is a) 60-80 b) 80-100 c) >100 d)
Last Answer : Answer: c Explanation: The octane number of natural gas is always >
Description : Major constituent of natural gas is a) ethane b) methane c) butane d) propane
Last Answer : Answer: b Explanation: Only methane is the major constituent of natural gas.
Description : The heating value per unit volume of hydrogen gas is less than ______________ that of air. a) 1/12th b) 1/10th c) 2/3rd d) 1/3rd
Last Answer : Answer: d Explanation: None
Description : Hydrogen gas has less than _______________ the density of air. a) 1/12th b) 1/10th c) 2/3rd d) 1/3rd
Last Answer : Answer: b Explanation: None.
Description : A gas engine has a volume of 300 cc and clearance volume of 25 cc. Its volumetric efficiency is 0.8 and mech efficiency is 0.9. What is the volume of the mixture taken in per stroke? (a) 248 cc (b) 252 cc (c) 264 cc (d) 286 cc
Last Answer : Ans : c
Description : In a petrol engine, which of the following gas gets exhausted out without burning and without transformation? a. CO2 b. CO c. O2 d. N2
Last Answer : ANSWER d. N2
Description : Which of the following is not an internal combustion engine? a. petrol engine b. steam turbine c. diesel engine d. gas turbine
Last Answer : ANSWER b. steam turbine
Description : A spark plug is used in a. petrol engine b. diesel engine c. gas engine d. steam engine
Last Answer : ANSWER a. petrol engine
Description : For perfect gas a. cp – cv = R b. cp + cv = R c. cp / cv = R d. cp X cv = R Where cp & cv are specific heats at constant pressure and volume.
Last Answer : ANSWER a. CP – CV = R
Description : Air standard cycle uses ____ as a working medium. a. Perfect gas b. Real gas c. Ideal gas d. Natural gas
Last Answer : ANSWER a. Perfect gas
Description : In sensible cooling process the relative humidity: A. decreases B. increases C. remains constant D. none of the above
Description : Humidification is the process of addition moisture in air at A. constant wet bulb temperature B. constant dry bulb temperature C. constant latent heat D. none of the above
Description : When, H1 = Total heat of air entering the coil (heating or cooling) H2 = Total heat of air leaving the coil (heating or cooling) H3 = Total heat of air at the end of ... A. cooling and humidification B. cooling and dehumidification C. heating and humidification D. heating and dehumidification
Description : Which of the following statement is true? A. the chart is plotted for pressure equal to 760mm Hg B. the constant wbt line represents adiabatic saturation process C. the constant wbt line coincides with constant enthalpy line D. all of the mentioned
Last Answer : ANSWER : D