Steam Boilers, Engines, Nozzles and Turbines The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and α = Nozzle angle) Vb = 0.5 V² cosα Vb = V cosα Vb = 0.5 V cosα Vb = V² cosα Vb = 0.5 V² cosα Vb = V cosα Vb = 0.5 V cosα Vb = V² cosα ANSWER DOWNLOAD EXAMIANS APP
Steam Boilers, Engines, Nozzles and Turbines In a reaction turbine when the degree of reaction is zero, then there is Maximum heat drop in moving blades No heat drop in moving blades No heat drop in fixed blades Maximum heat drop in fixed blades Maximum heat drop in moving blades No heat drop in moving blades No heat drop in fixed blades Maximum heat drop in fixed blades ANSWER DOWNLOAD EXAMIANS APP
Steam Boilers, Engines, Nozzles and Turbines Which is not the correct statement about moisture in coal? Inherent moisture and surface moisture are different things Some moisture in coal helps in better burning which is not possible with completely dry coal In some coals moisture may be present up to 40% It increases thermal efficiency Inherent moisture and surface moisture are different things Some moisture in coal helps in better burning which is not possible with completely dry coal In some coals moisture may be present up to 40% It increases thermal efficiency ANSWER DOWNLOAD EXAMIANS APP
Steam Boilers, Engines, Nozzles and Turbines Calorific value of coal is of the order of 5000-8000 kcal/ kg 2000-4000 kcal/ kg 800-1200 kcal/ kg 200-400 kcal/ kg 5000-8000 kcal/ kg 2000-4000 kcal/ kg 800-1200 kcal/ kg 200-400 kcal/ kg ANSWER DOWNLOAD EXAMIANS APP
Steam Boilers, Engines, Nozzles and Turbines For a Parson's reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then α₁ = α₂ and β₁ = β₂ α₁ = β₂ and β₁ = α₂ α₁ < β₁ and α₂ > β₂ α₁ = β₁ and α₂= β₂ α₁ = α₂ and β₁ = β₂ α₁ = β₂ and β₁ = α₂ α₁ < β₁ and α₂ > β₂ α₁ = β₁ and α₂= β₂ ANSWER DOWNLOAD EXAMIANS APP
Steam Boilers, Engines, Nozzles and Turbines Thermal efficiency of well maintained boiler will be of the order 0.75 0.5 0.4 0.9 0.75 0.5 0.4 0.9 ANSWER DOWNLOAD EXAMIANS APP
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