Engineering Questions with Answers - Multiple Choice Questions
Mechanical Operations MCQ’s – Shrouded Turbine
Which of the following is the correct energy conversion in a wind turbine?
a) Electrical energy to kinetic energy
b) Electrical energy to mechanical energy
c) Kinetic energy to electrical power
d) Kinetic energy to any desired form of energy
Explanation: A wind turbine is a machine that is capable of capturing the mechanical energy of the wind and converting it to electrical power. Wind turbine doesn’t capture electric energy rather, it is the end product.
Which of the following is true about Betz Law?
a) Any wind turbine cannot convert more than 16/27 of wind’s kinetic energy
b) Any wind turbine cannot convert more than 17/27 of wind’s kinetic energy
c) The theoretical maximum power efficiency of any turbine is 0.63
d) The theoretical maximum power efficiency of any turbine is 0.64
Explanation: Betz law states that no wind turbine can convert more than 16/27 of the kinetic energy of the wind, into mechanical energy that turns a rotor. The theoretical maximum power efficiency of a wind turbine is 0.59.
Which of the following is false about the power coefficient of a wind turbine?
a) It is the actual maximum power efficiency of a turbine
b) It is a constant value for all turbines
c) Ideally, its value lies between 45 and 50
d) Power coefficient has a maximum value of 0.58
Explanation: The power coefficient is a unique value that differs for every turbine. The theoretical maximum value of power coefficient is 0.59. In real life application, the actual power coefficient lies between 45 and 50.
Which of the following determines the power available in a shrouded turbine?
a) Power available = CP * (Ideal Power)-1
b) Power available = CP * (Ideal Power)
c) Power available = CP * (Ideal Power)2
d) Power available = CP * (Ideal Power)1/2
Explanation: The actual power available is numerically less than the ideal power calculated. It is equal to the product of the power coefficient and the power calculated using formula Ideal power = 12ρAv3. The power coefficient is a value that differs for every turbine.
Pick the odd one out with respect to the different types of turbines.
a) Upwind turbine
b) Shrouded turbine
d) Downwind turbine
Explanation: While the rest of the turbines are HAWT (Horizontal Axis Wind Turbine), Anemometer is a VAWT (Vertica Axis Wind Turbine). A horizontal axis wind turbine has an axis of rotation parallel to the wind stream. VAWT produces less energy when compared to HAWT however, the former is more suitable when the space is limited.
Which of the following is false with respect to turbines?
a) Augmenters decrease wind passage through blades
b) The blades of VAWT are prone to fatigue
c) VAWT is not as common as HAWT
d) Savonius wind turbine look like an S form the top
Explanation: Shrouded turbines have structures called augmenters that ensure maximum possible air passage through the wind blades. VAWT cannot take the advantage of higher wind speed at higher altitudes, which is why it is relatively less preferred when compared to HAWT. The blades of VAWT are prone to fatigue because highly turbulent forces act on these blades.
Which of the following is not true about shrouded turbines?
a) Turbines are hidden in shrouds
b) High bio fouling
c) Suitable geometry can increase flow velocity
d) Most of these turbines are directional
Explanation: Since turbines are hidden in shrouds, they are less affected by floating debris. Shrouded turbines are protected from light, and thereby have low bio fouling. Appropriate geometry can increase flow velocity, 3 to 4 times than open or free velocity