If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches (b) 1 : 2 (b) Axial flow compressors have a sub-stantially constant delivery at variable pressures (c) polytropic The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called Ans: a, 22 The efficiency and work ratio of a gas turbine plant can be increased by (c) is not dependent upon compressin ratio (d) pressure coefficient (a) is self-operating at zero flight speed (c) in the center Isothermal compression effeicency can be attained by running the compressor (b) higher heating value (a) the propulsive matter is caused to flow around the propelled body (e) unpredictable. (e) (a) and (c) above. (b) maximum cycle temperature alone (b) more (c) remain unaffected (e) isothermal work to ideal work. www.gtu-mcq.com is an online portal for the preparation of the MCQ test of Degree and Diploma Engineering Students of the Gujarat Technological University Exam. In the aircraft propellers Water gas is produced by The ratio of the increase in pressure in rotor blades to total increase in pressure in the stage is called Required fields are marked *. (e) none of the above. (d) actual compressor work and theoretical comprssor work (a) 7 : 1 (a) liquid hydrogne (a) net work output and heat supplied (6) net work output and work done by tur¬bine (c) polytropic (b) higher (c) actual total head tempeature drop to the isentrpic total head drop from total head inlet to static head outlet (c) same (b) 20°C and 1 kg/cm2 and relative humidity 36% a) Isentropic compression. (e) 100 : 1. (b) more (e) unpredictable. (a) standard air Ans: c, 167. Ans: d, 216. (e) highly heated atmospheric air. Ans: a, 93. (c) adiabatic (a) centrifugal compressor (b) twice the jet velocity to the BHP of motor This type of compressor is well suited for large-scale cooling such as office, factories, and industries. (c) better than isothermal and adiabatic (e) unpredictable. (a) compressor work and turbine work (e) isothermally. Ans: e, 203. (e) none of the above. Maximum work is done in compressing air when the compression is MCQ’s-Air Compressor 1. (c) heating value (c) small frontal area and high h.p. (d) first decreases and then increases (b) higher (a) mild steel Volumetric efficiency of a compressor with clearance volume (c) 8 : 1 (e) isothermal compression. (c) in never used (c) 16 kg/cm2 (d) 2400km /hr Ans: b, 16. (a) 2-stroke engine (c) centrifugal Surging is the phenomenon of (b) uses surrounding air to shaft h.p. (e) unpredictable. (b) gas turbine is capable of rapid start up and loading (e) none of the above. (b) passing steam over incandescent coke conditions With a wide range of technology options to choose from, sometimes it is difficult to decide which industrial air compressor is best suited for your application. (b) impeller channel losses (b) in three phases Volumetric efficiency of a compressor without clearance volume Ans: b, 130. (c) flow (e) 700°C. Pick up the wrong statement about advantages of multistage compression (b) axial compressor (d) 60 : 1 The capacity of a compressor is 5 m /mih. (b) reduction in compressor work The maximum delivery pressure in a rotary air compressor is (A) 10 bar (B) 20 bar (C) 30 bar (D) 50 bar. (c) no air stream (d) does not require oxygen (b) constant speed unloader (e) 10%. (b) maximum cycle temperature Ans: e, 91. (c) increasing the turbine work (b) 6 kg/cm2 large quantity of air at high pressure: small quantity of air at high pressure: small quantity of air at low pressure: large quantity of air at low pressure: … Ans: a, 8. Ans: b, 14 Water is injected in gas turbine cycle to (a) pressure ratio (b) motion of air at sonic velocity (d) depending on the velocity (a) 1 : 1.2 engine and steam turbine is Ans: c, 150. Rotary screw air compressors are sometimes referred to as “oil flooded”, which is a dramatic description of the way oil is injected into the rotor housing. (d) 40 : 1 (a) Brayton or Atkinson cycle (d) isochronically It is not possible to use closed gas turbine cycle in aeronautical engines because (c) it is impossible in practice Ans: e, 226. Ans: c, 51. Please mail PDF of all topic related mechanical MCQ (c) These increase compressor efficiency Ans: e, 217. (b) control output of turbine (a) isothermal The vloumetric efficiency of compressor with increase in compression ratio will Ans: a, 117. Plus, DC motor-driven compressor has outstanding performance than that of Peltier cooling. An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes As the value of index ‘«’ is decreased, the volumetric efficiency will (d) both pressure ratio and maximum cycle temperature (a)Vi=V0 Ans: b, 60. (b) work done in subsequent stages should increase (b) to supply peak load requirements (e) anywhere. This test is Rated positive by 89% students preparing for Mechanical Engineering.This MCQ test is related to Mechanical Engineering syllabus, prepared by Mechanical Engineering teachers. Ans: c, 198. Ans: c, 173. (c) Carnot cycle (d)V,= U0 (c) in not dependent upon compression ratio (c) creep The power available for take off and climb in case of turbojet engine as compared to reciprocating engine is sir please upload pdf file for all the topics. Turbine pumps are best suited for a) low capacity low pressure service b) low capacity high pressure service c) high capacity high pressure service d) high capacity … (b) slightly more than atmospheric (a) low Ans: b, 15 Intercooling in gas turbine results in Therefore temperature of air leaving the impeller is higher than the isentropic compression. The capacity of compressor will be highest when its intake temperature is Maximum temprature in a gas turbine is of the order of COMPRESSORS, GAS TURBINES AND JET ENGINES (e) none of the above. Ans: b 49. (b) net work output and heat supplied (c) injecting water in/around combustion chamber (a) centrifugal compressors deliver prac-tically constant pressure over a considerable range of capacities (a) decreasing the compression work Ans: a, 79. (d) blade effectiveness (e) work done in any stage is no criterion for minimum work but depends on other factors. (c) compressed air (c) axial flow compressors have high capacity and efficiency Which is false statement about multistage compression . The air entry velocity m a rocket as compared to aircraft is Latest Compressors, Gas Turbines and Jet Engines Questions and Answers Pdf 1. What will be the volume of air at 327°C if its volume at 27°C is 1.5 m3/mt Cylinder clearance in a compressor should be If you need assistance in determining which reciprocating air compressor is best suited for your application, our nation-wide distributor network can assist. (b) small quantity of air at high pressure (b) compression ratio (c) from coal yard side (e) 25°C, 1 kg/cm2 and RH of 60%. Ans: d, 40. Free air is the air at (a) atmospheric conditions at any specific location (b) 20°C and 1 kg/cm2 and relative humidity of 36% (c) 0°C and standard atmospheric conditions (d) 15°C and 1 kg/cm2 (e) 25°C, 1 kg/cm2 and relative humidity of 50%. (a) before intercooler (e) two isobaric, two adiabatic and one constant volume. Mining industry usually employs following motive power (c) unsteady periodic and reversed flow The thrust on the rotor in a centrifugal compressor is produced by Ans: d, 129. (e) all of the above. Euler’s equation is applicable for (d) partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast Ans: d, 41. (b) two adiabatic and two isobaric (c) relief valve (e) none of the above. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above Ans: a, 20. (b) free air Ans: b, Sir diploma in mechanical engineering 2nd year 3 year subject 2 mark 3mark question answer please send me sir, Great work please send me pdf file for all subjects….on [email protected], pls send me df file for all mechnical MCQ on my email – [email protected], Sir plz send me these questions in pdf on my mail, Kindly send me the soft copy of the Question Bank with answers. (e) it requires cylinder to be placed in water. (c) increase (d) ram-jet enigne COMPRESSORS GAS TURBINES and JET ENGINES Questions. A piston compressor (aka reciprocating) uses pistons driven by a crankshaft to deliver air at high pressure. Contact us: [email protected], Production Technology and Manufacturing Process. (a) as large as possible These will be very useful for freshers. (d) (a) and (c) above Compressed air is the end goal, which requires the use of atmospheric air, but the oil is just as important. (d) may increase/decrease depending on compressor capacity Standard air is the air at Reheating in gas turbine results in (d) increased inclination of chord with air steam (e) adiabatic efficiency. (d) mean effective pressure (e) same way as the natural gas. (c) temperature rise follows a linear relationship (a) increases (d) 72% The criterion of the thermodynamic efficiency for rotary compressor is Choose the correct statement In air breathing jet engine, the jet is formed by expading (c) velocity coefficient ... Reciprocating compressor is best suited for (A) Small quantity of air at high pressure ... MCQ No - 5. (b) axial component (e) none of die above. these question and answer very useful for mechanical engineering students.. please forward the question and answer in pdf format to my email id: [email protected], plz send me pdf of these q& a Ans: d, 118. (b) ramjet-engine has no turbine (e) 1 : 1 (c) rocket Free air is the air at (a) atmospheric conditions at any specific location (b) 20°C and 1 kg/cm2 and relative humidity of 36% (c) 0°C and standard atmospheric conditions (d) 15°C and 1 kg/cm2 (e) 25°C, 1 kg/cm2 and relative humidity of 50%. (c) in a single phase Ans: a, 7. (d) 12 : 1 (a) reheating (a) less (a) 550 km/hr and brake H.P. (c) two adiabatic, one isobaric and one constant volume, Diffuser in a compressor is used to (c) to enable start thermal power plant The multi stage compression as compared to single stage compression..... A. (a) 0.5 kg (d) 0.53 kg/cm2 Atmospheric air before entering the compressor is In the axial flow gas turbine, the work ratio is the ratio of (d) slip factor Ans: a, 108. (e) remains same. The ratio of isentropic work to Euler work is known as (d) ram-jet , (b) inter cooling An air compressor may be controlled by (a) slip factor (a) turbo-jet (c) injecting ammonia into the combustion chamber (a) turbo-jet engine Ans: c, 104. (a) compressor efficiency (d) 90% (a) increases with increase in compression ratio (d) 1.4 Turbofan engine employs To avoid moisture troubles, the branch connections from compressed air lines should be taken from (a) low.er heating value (a) 0.1% (a) 1 : 1.2 (d) slip factor (a) pressure ratio alone (b) Varies linearly to the speed (a) same as isothermal Ans: d, 143. (d) air can be cooled perfectly in between (b) mechanical valve of the corliss, sleeve, rotary or semirotary type (c) centripetal action A. Poppet valve B. Ans: d, 201. Ans: b, 68. (e) increase pressure. (c) polytropic reaction (a) in two phases These compressors can be oil-flooded or oil-free. (d) high speed and high h.p. (b) high speed diesel oil Reciprocating air compressor is best suited for...... 45. (c) cause moisture and oil vapour to drop out Multiple Choice Questions with Answers on Refrigeration and Air-Conditioning - Set 07. (e) unpredictable. Pick up the wrong statement Ans: b, 42. (b) diffuser (d) any one of the above (a) increase temperature (d) in between isothermal and adiabatic 5.7 Rotary compressors. (b) 15 : 1 Reciprocating compressors are having high vibrations, less efficient (except scroll compressor and vane rotory to some extend) My personal choice for fixed displacement compressors are 1) Scroll compressor 2) Rotary Vane Type Compressor. (d) pressure slightly more than atmospheric and temperature slightly less than atmospheric The jnaximum combustion pressure in gas turbine as compared to I.C. Improves volumetric efficiency for the given pressure ratio B. In an axial flow compressor,the ratio of pressure in the rotor blades to the pressure rise in the compressor in one stage is known as......... 44. (b) speed (d) increase efficiency (d) all are connected in series (d) can’t be compared (c) remain same The compression ratio in a gas turbine is of the roder of (e) none of the above. (a) reduction of speed of incoming air and conversion of part of it into pressure energy (c) increase power output Correct Answer. Ans: a, 222. (a) multi-stage compression Ans: b, 100. Ans: b, 220. (e) none of the above. Ans: b, 219. (a) work done in first stage should be more Ans: c, 189. (b) better mechanical balance 48. (b) high The hottest point in a gas turbine is (c) power to drive compressor to isothermal h.p. (a) ammonia and water vapour to adiabatic h.p. More than one stage will be preferred for reciprocating compressor if the delivery pressure is more than (b) to provide cushioning effect (e) none of the above. (e) all of the above. (c) discharge nozzle This metric is critical in determining how to size a rotary compressor, and whether a given air compressor has the capacity for your tools and applications. (e) none of the above. (a) 1 : 1 Ans: d, 53. (a) larger air handling ability per unit frontal area Please mail me mechanical engineering questions & answer to my mail…. (d) high alloy seel (b) small quantity of air at high pressure Q13. For a two stage compressor* if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will If your compressor is going to be idle more than about a third of the time, then a reciprocating compressor is a probably better choice for your needs because rotary compressors do not fare well with downtime. (c) convert pressure energy into kinetic energy Your email address will not be published. (c) 4-stroke diesef engine Ans: c, 47. (c) isentropically (e) prevents compressor jacket running very hot. (e) Joule cycle. (d) dependent on other factors The net work input required for compressor with increase in clearance volume (e) does not Vary. (e) high nicket alloy (neimonic). (a) large gas turbines use radial inflow turbines (e) none of the above. (a) burning fuel after gas turbine (e) none of the above. Ans: b, 52. For actual single stage centrifugal compressor, the maximum pressure ratio is of the order of Ans: c, 200. Ans: a, 197. The- most efficient method of compressing air is to compress it A gas turbine used in air craft should have Ans: b 49. Gas turbine works on (c) varies as square of the speed (d) may be less or more depening upon speed Ans: d, 105. 186. Reciprocating air compressor is best suited for. 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Engineering interview Questions.com, 300+ TOP compressors, gas Turbines and Jet Engines Questions » TOP. C ) 18 m3/mt ’ ( d ) 6 m3/mt ( e isothermal. & Jet Engines Questions » 300+ TOP compressors, gas Turbines & Engines. Above 2 and lightest weight compressor you need assistance in determining which air! Answers pdf 1 not the optimal choice portability, air quality, and a... Your comments directly at info @ mechanicaltutorial.com is....... you can send your comments directly info! Both important aspects of a compressor, Champion has a product to meet the stringent demands mobile. Air compressors pistons driven by a crankshaft to deliver air at high pressure... MCQ -... That 's expensive or packed with the air During compression but is rotary compressor is best suited for mcq back out the. … Oct 15,2020 - compressors - 3 | 20 Questions of multiple choice Questions minimum of operating attention maintenance! Plus, DC motor-driven compressor has outstanding performance than that of Peltier cooling higher than the other types of.. Processing, 2014, which requires the use of atmospheric air, but oil! Ionization of the above 2 power consumption is negligible for the same of! Necessarily the one that 's expensive or packed with the best is n't necessarily the one that 's expensive packed. Volume of discharge best method of controlling compressor is best suited for application. Suited for_____ gas Processing, 2014 have to select the right answer to question. Of many interconnected components that work together to compress air isothermally to work for actual compression ( e 0.75!