Description : In a single stage reciprocating air compressor, the work done on air to compressor is from suction pressure to delivery pressure will be minimum when the compression is A. Isothermal process B. Adiabatic process C. Polytropic process D. Constant pressure process.
Last Answer : ANSWER : A
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
Last Answer : ANSWER : C
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 : A large clearance volume in a reciprocating compressor results in A. Reduced volume flow rate B. Increased volume flow rate C. Lower suction pressure D. Lower delivery pressure
Description : A large clearance volume in reciprocating compressor results in A. reduced volume flow rate B. Increased volume flow rate C. Lower suction pressure D. Lower delivery pressure
Description : In vapour compression cycle using NH3 as refrigerant, initial charge is filled at (a) suction of compressor (b) delivery of compressor (c) high pressure side close to receiver (d) low pressure side near receiver
Last Answer : Ans: c
Description : In four stroke engine which of the following is also known as power stroke a. Suction stroke b. Compression stroke c. Expansion stroke d. Exhaust stroke (Ans:c) Measurements of fuel and air ... into IC engine,___________its efficiency A. increase B. decrease C. does not alter D. unpredictable on
Description : Which one of the following statement is not correct for the volumetric efficiency of a reciprocating air compressor? A. It decreases with increase in ambient temperature B. It increases with ... It increases with decrease in clearance ratio D. It decreases with increases in delivery pressure
Description : Fuel is injected into the cylinder at the end of ______________ stroke. a) suction b) compression c) expansion d) exhaust
Last Answer : Answer: b Explanation: Fuel is injected into the cylinder at the end of compression stroke and not at suction or expansion stroke.
Description : The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is (a) bigger (b) smaller (c) equal (d) smaller/bigger depending on capacity
Last Answer : Ans: a
Description : The ratio of work done per cycle to the stroke volume of the compressor is known as A. Compressor capacity B. Compression ratio C. Compressor efficiency D. Mean effective pressure
Last Answer : ANSWER : D
Description : Acceleration head in a reciprocating pump (A) Increases the work done during delivery stroke (B) Decreases the work done during suction stroke (C) Does not change the work requirement of the pump (D) Increases the work done during suction stroke
Last Answer : (C) Does not change the work requirement of the pump
Description : A reciprocating compressor is not suitable for use as a supercharger because: A. it runs at lower rpm B. the pressure ratio is high C. volumetric efficiency is high D. it is bulky and can handle small quantity of air
Description : In reciprocating air compressor the clearance ratio is given by A. B. C. D.
Description : Which one of the following statements are correct for reciprocating air compressor? A. Its volumetric efficiency increases with increasing clearance ratio B. Its volumetric efficiency increases ... ratio D. Its volumetric efficiency decreases with increasing clearance ratio and pressure ratio
Description : In a reciprocating air compressor the compressor work per kg of air A. Increases as clearance volume increases B. Decreases as clearance volume increases C. Is independent of clearance volume D. Increases with clearance volume only of multistage compressor
Description : Reducing suction pressure in refrigeration cycle (a) lowers evaporation temperature (b) increases power required per ton of refrigeration (c) lowers compressor capacity because vapour is lighter (d) all of the above.
Last Answer : Ans: d
Description : In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to (a) collect liquid refrigerant and prevent it from going to compressor (b) detect liquid in vapour (c) superheat the vapour (d) increase refrigeration effect
Description : The domestic refrigerator uses following type of compressor (a) centrifugal (b) axial (c) miniature sealed unit (d) piston type reciprocating
Description : Which one of the following types of compressor is mostly used for supercharging of IC engines? (a) Radial flow compressor (b) Axial flow compressor (c) Root blower (d) Reciprocating compressor
Last Answer : Ans : c
Description : Compressor mostly used for supercharging of IC engine is A. Radial flow compressor B. Axial flow compressor C. Root blower compressor D. Reciprocating compressor
Description : Reciprocating compressor are provided with A. Simple disc/plate valve B. Poppet valve C. Spring-loaded disc valve D. Solenoid valve.
Description : Which one of the following type of compressor is mostly used for supercharging of I.C engine A. Radial flow compressor B. Axial flow compressor C. Root blower D. Reciprocating compressor.
Description : The specific speed of a centrifugal compressor is generally A. less than that of reciprocating compressor B. independent of compressor type, but depends only on size of compressor C. higher ... axial compressor D. more than specific speed of reciprocating compressor but less than axial compressor
Description : Which of the following engine can work on very lean mixture a. Spark ignition engine b. compression ignition engine c. two stroke engine d. Four stroke engine
Last Answer : ANSWER b. compression ignition engine
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
Description : For minimum work input in a two stage compression process the intermediated pressure is the A. Arithmetic process of suction and discharge pressure B. Logarithmic mean of suction and discharge pressure C. Geometric mean of suction and discharge pressure D. Hyperbolic mean of suction and discharge
Description : With suction pressure being atmospheric, increase in delivery pressure with fixed clearance volume A. increase volumetric efficiency B. decrease volumetric efficiency C. does not change volumetric efficiency D. First increase volumetric efficiency and then decrease it
Description : The clearance volume of the air compressor is kept minimum because A. It allows maximum compression to be achieved B. It greatly affects volumetric efficiency C. It results in minimum work D. It permits isothermal compression
Description : Work input to the air compressor with n as index of compression A. Increases with increase in value of n B. Decrease with increase in value of n C. remains same whatever the value of n D. first increase and then decreases with increase of value of n.
Description : Which one of the following methods can be adopted to obtain isothermal compression in an air compressor? A. Increasing the weight of the compressor B. Inter-stage heating C. Atmospheric cooling D. Providing appropriate dimensions to the cylinder
Description : The volume of air delivered by the compressor is called A. Free air delivery B. Compressor capacity C. Swept volume D. Mean effective pressure
Description : The maximum delivery pressure in a rotary air compressor is A. 10 bar B. 20 bar C. 30 bar D. 50 bar
Description : Consider the following statements: Air vessels are fitted on the suction and delivery sides of a reciprocating pump to 1. Achieve higher speed without separation. 2. Reduce work in overcoming frictional resistance. 3. Avoid excessive vibration ... 2 & 3 only (c) 2, 3 & 4 only (d) 1, 2, 3 & 4
Last Answer : (d) 1, 2, 3 & 4
Description : Intercooling in multistage compression is done A. To cool the air during compression B. To cool the air at delivery C. To enable compression in two stages D. To minimize the work of compression
Description : In two stroke engine, which of the following functions are performed at the same time? a. Compression and exhaust b. Intake and Expansion c. Intake and exhaust d. Intake and compression (Ans:c)
Last Answer : The compression ratio in a Compression Ignition (CI) engine is generally in between a. 8 to 13 b. 14 to 23 c. 20 to 28 d. 25 to 32 (Ans:b)
Description : The coefficient of performance is the ratio of the refrigerant effect to the (a) heat of compression (b) work done by compressor (c) enthalpy increase in compressor (d) all of the above
Description : Where does the lowest temperature occur in a vapour compression cycle ? (a) condenser (b) evaporator (c) compressor (d) expansion valve
Last Answer : Ans: b
Description : In vapour compression refrigeration system, refrigerant occurs as liquid between (a) condenser and expansion valve (b) compressor and evaporator (c) expansion valve and evaporator (d) compressor and condenser
Description : The higher temperature in vapour compression cycle occurs at (a) compressor discharge. (b) expansion valve (c) evaporator (d) condenser discharge
Description : In vapour compression cycle the condition off refrigerant is dry saturated vapour (a) after passing through the condenser (b) before passing through the condenser (c)before entering the expansion valve (d) before entering the compressor
Last Answer : Ans: D
Description : Adiabatic compression is one in which A. Temperature during compression remains constant B. No heat leaves or enters the compressor cylinder during compression C. Temperature rise follows a linear relationship D. Work done is maximum.
Description : In multi stage compressor, the isothermal compression is achieved by A. Employing intercooler B. By constantly cooling the cylinder C. By running compressor at very slow speed D. By insulating the cylinder
Description : Volumetric efficiency of a compressor without clearance volume A. Increases with increase in compression ratio B. Decreases wit increase in compression ratio C. Not dependent upon compression ratio D. Unpredictable
Description : With increase in compression ratio, the volumetric efficiency of air compressor (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease (depends on the suction pressure)
Last Answer : Option A
Description : At what value of crank angle (roughly), no flow of water from or into the air vessel takes place in case of a double acting reciprocating pump? (A) 40° and 140° (B) 45° and 60° (C) 90° and 80° (D) 20° and 120°
Last Answer : (A) 40° and 140
Description : The fuel air ratio in a petrol engine fitted with suction carburetor, operating with dirty air filter as compared to clean filter will be A. higher B. lower C. remain unaffected D. unpredictable
Description : In a naturally aspirated diesel engine, the air is supplied by a A. supercharger B. centrifugal pump C. movement of engine piston D. reciprocating pump
Description : Which one of the following statements is correct? A. Reciprocating compressors are used to supply large quantities of air at a lower pressure ratio B. Centrifugal compressors are used to supply ... . Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.
Description : In reciprocating compressors, one should aim at compressing the air A. Adiabatically B. Isentropically C. Isothermally D. Polytropically