70651. In jet propulsion power unit, the inlet duct of diverging shape is used for converting kinetic energy of air into pressure energy.
70652. The temperature of air at the beginning of the compression stroke is __________ the atmospheric temperature.
70653. The compressor efficiency is defined as the ratio of volume of free air delivery per stroke to the swept volume of the piston.
70654. In a gas turbine, air is obtained from the atmosphere and compressed in an air compressor.
70655. In open cycle turbo-jet engines used in military aircraft, reheating the exhaust gas from the turbine by burning, more fuel is used to increase the
70656. Gas turbine as compared to internal combustion engine
70657. A closed cycle gas turbine consists of a
70658. For maximum work, the reheating should be done to an intermediate pressure of (where p1 = Maximum pressure, and p2 = Minimum pressure)
70659. The intercooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p1 = Intake pressure of air, p2 = Intercooler pressure, and p3 = Delivery pressure of air)
70660. The pressure of air at the beginning of the compression stroke is __________ the atmospheric pressure.
70661. The pressure ratio in a centrifugal compressor can be increased by increasing the tip speed and lowering the inlet temperature.
70662. Free air is the air at atmospheric conditions at any specific location.
70663. A gas turbine used in air-craft should have low weight and small frontal area.
70664. A closed cycle gas turbine works on
70665. The clearance, in a single stage, single acting reciprocating air compressor does not effect the workdone on the air and the power required for compressing the air.
70666. Air motors work on the cycle which is the reverse of the reciprocating air compressor cycle.
70667. Which of the following statement is correct relating to rocket engines ?
70668. In reciprocating air compressors, isothermal efficiency is used for all sorts of calculations.
70669. Euler's equation can be used for
70670. A rocket engine uses __________ for the combustion of its fuel.
70671. The perfect intercooling, in multistage compression, means that the temperature of air at inlet to subsequent stages is equal to the initial temperature.
70672. In a compressed air system, the temperature of air discharged from the air motor is __________ than the initial compressor intake temperature.
70673. The efficiency of roots blower __________ with the increase in pressure ratio.
70674. The operation of lifts, rams and pumps make use of compressed air.
70675. A jet engine has
70676. A receiver in compressor installations is used to damp pressure waves in compressor discharge.
70677. A compressor at high altitudes will require __________ power.
70678. The mean effective pressure of the compressor is the
70679. The reason for volumetric efficiency of reciprocating compressor being less than 100 percent is
70680. For minimum work in multi-stage compression, the workdone on all stages should be equal.
70681. The thrust of a jet propulsion power unit can be increased by
70682. Sum of exterior angles and interir angles of a regular hexagon is
70683. Slip factor in a centrifugal compressor indicates the amount of air leaked from the storage vessel.
70684. The ratio of the isentropic work to the Euler's work is known as pressure coefficient.
70685. A turbo-prop is preferred to turbo-jet because
70686. The air power of the compressor is also known as
70687. The overall isothermal efficiency of the compressor is defined as the ratio of
70688. The minimum work required for a three stage reciprocating air compressor is __________ the work required for each stage.
70689. For a multi-stage compressor, the polytropic efficiency is constant throughout for all the stages.
70690. In a high pressure compressor, the delivery pressure is
70691. When the outlet angle from the rotor of a centrifugal compressor is more than 90°, then the blades are said to be
70692. In axial flow compressors, the flow of air is parallel to the axis of compressor.
70693. The ratio of the isothermal power to the shaft power or brake power of the motor or engine required to drive the compressor is called overall isothermal efficiency.
70694. In a double acting compressor, the air is compressed
70695. The basic principle of the rocket propulsion is the same as that of jet propulsion.
70696. In a centrifugal compressor, the flow of air is __________ to the axis of compressor.
70697. For minimum work required to compress and deliver a quantity of air by multi-stage compression,
70698. Separators are generally used in air compressor installations
70699. If the flow of air through the compressor is perpendicular to its axis, then it is a
70700. In air compressors, free air delivery means the