8575791
| Pregunta | Respuesta |
| Compressors | Fans that generate pressure differences in excess of 30 IWG |
| Fan | A fluid machine that is used to move and induce flow of a gas (also referred to as a blower) |
| Major Head Loss | Pressure loss due to viscous effects in fully developed flow in constant area pipes or ducts |
| Minor Head Loss | Pressure loss due to entrances, fittings, valves, and area changes |
| Analysis | Application of principles to a well defined problem |
| Design | Applications of principles to an undefined, open problem; not 1 correct answer |
| What are the general steps of Design? | 1. Develop preliminary specifications/constraints 2. Detailed specs, evaluate concepts, perform feasibility study 3. Detailed design and economic analysis 4. Present design with results of analysis 5. Fabricate and test prototype 6. Fabricate and manufacture 7. Market product |
| Reynold's Number | Characterizes the flow regime (laminar vs. turbulent); inertial force over viscous force |
| Friction Factor | Used to predict head loss based on the friction of the pipe (refer to Moody's Diagram) |
| Moody's Diagram | A family of curves that relate the friction factor to the relative roughness of the pipe |
| Hydraulic Diameter | Used when handling flow in noncircular pipes/ducts |
| Typical Performance Curve | Curves of the external static pressure vs the volume flow rate of a fan operating at various speeds |
| Shut-off Point | No flow occurs when the external static pressure is maximum |
| Free-Delivery Point | External static pressure is a minimum so volume flow rate is a maximum |
| Fan Laws | Relationships among the various performance parameters that can determine new values as a result of new changes (Ex. flow rate, fan speed, gas density) |
| Pump | Moves liquid, adds energy to keep the fluid moving, overcomes head loss, and/or build pressure to overcome elevation |
| Pump Capacity | Volume flow rate of fluid through the pump |
| Pump Net Head | Increases fluid energy; absolute pressure at the head of the pump |
| Water Horsepower | Power delivered directly to the fluid by the pump |
| Brake Horsepower | External power supplied to the pump by a mechanical shaft or motor |
| Pump Efficiency | Ratio of useful power to supplied power |
| Pump Performance/ System Curves | Curves of height, efficiency, and bhp as functions of volume flow rate |
| Cavitation | The formation of bubbles or cavities in liquid, developed in areas of relatively low pressure (negative effects on the pump) |
| NPSH(R) | Net Pump Suction Head (Required); used to ensure inlet pressure is greater than vapor pressure to avoid cavitation |
| Open-loop Piping | Some part of the circuit is open to the atmosphere |
| Closed-loop Piping | No points are open to the ambient/surroundings |
| Heat Exchanger | Devices that facilitate energy transfer between two fluids at different temperatures without the fluids mixing |
| Double Pipe Heat Exchanger | One fluid flows through a pipe and the other fluid flows through the space surrounding said pipe |
| Overall Heat Transfer | The amount of heat moved across the surfaces in a heat exchanger |
| Thermal Resistance Network | A series of resistances to the flow of heat through boundaries within the system |
| Nusselt Number | Nondimensionalized heat transfer coefficient |
| Dittus-Boelter Correction | Used to determine the Nusselt number for fully developed turbulent flow in smooth tubes |
| Log-Mean Temperature Difference Method | Used to determine heat transfer surface area, the outlet temperatures of the fluid, or the heat transfer rate |
| Effectiveness of Heat Exchanger | Efficiency of exchanging energy between the two fluids |
| Number of Transfer Units | Number of items transferring energy within the system |
| Number Transfer Unit Efficiency Method (e-NTU) | Method for heat transfer design and performance analysis |
| Check Valve | Prevents Backflow of water into the boiler when the pump is not energized |
| Relief Valve | Protects the boiler from excessive pressure buildup and possible rupture |
| Hydronic Heating Systms | Hot water, multicomponent systems used to heat water; also can be used to heat infrastructures |
| Feedwater | A line that supplies fresh plant or building water to a boiler |
| I=B=R | Most conservative rating system for larger capacity boilers and water heaters |
| AFUE | Annual Fuel Utilization Efficiency of the boiler |
| Orifice Plate/ Balancing Valve | Used to improve (flow) balance within the system |
| Gas Cycle | Working fluid remains as a gas throughout the entire cycle |
| Brayton Cycle | Type of gas cycle; gas-turbine system based on air or combustion gas as the working fluid |
| Vapor Cycle | The working fluid is a gas in one part of the cycle and a liquid in another |
| Rankin Cycle | Type of vapor cycle; steam turbine system with pressurized, superheated steam entering and liquid water leaving |
| Carnot Cycle | An ideal reversible cycle that can operate between two constant temperature reservoirs |
| Contact/Open Feedwater Heater | Direct mixing of steam with liquid water |
| Surface/Closed Feedwater Heater | No direct mixing of steam and liquid water |
| Reheater | Reheats partially expanded steam; increases performance and life of the turbine |
| HHV | Higher heating value |
| LHV | Lower heating value |
| DCA | Drain Cooler Approach; Method to find temperature of inlet water; drain cooler collects liquid condensate to recover energy |
| TTD | Terminal Termperature Difference; for a drain cooler; method to find the exiting pipe water temperature |
| Steam Turbine | Component that generates the power that is converted to electrical power by the generator |
| Impulse Turbine | Steam expands in stationary nozzles |
| Reaction Turbine | Steam expands in both stationary nozzles and across moving blades |
| Expansion Line End Point | The steam conditions at the exit of the last stage of the LP Turbine |
| Used Energy End Point | Steam conditions at the condenser inlet |
| Mollier Diagram | Plots straight expansion lines between h in and out to find enthalpies of the steam bled from the turbine |
| NHR | Ratio of the total heat input to the net generator output |
| Availability | Reversible work produced when the cycle working fluid changes to the state that is in thermal and mechanical equilibrium with the environment |
| Gas Turbine | Air or combustion gas mixture is the working fluid |
| Economizer | The section of the boiler in which compressed water is heated but not vaporized |
| Water Hammer | A large pressure surge that shakes and breaks pipes |
| Steam Blanketing | Occurs when steam and liquid water are not mixed (causes erosion of the pipes) |
| Evaporator | Section of the pipe that serves to reduce the exhaust gas temperature and bring the water to boiling point |
| Superheater | Steam is superheater for the steam turbine |
| Turbine | A machine for which power is continuously produced by a working fluid moving a wheel or motor |
| Balance Damper | Control dampers that balance the flow of air but are not intended for a positive shutoff or automatic control |
| PVC | Polyvinyl Chloride |
| CPVC | Chlorinated Polyvinyl Chloride |
| PEX | Cross-linked Polyethylene |
| ABS | Acrylonitrile Butadiene Styrene |
| Surge | Sudden powerful forward or upward movement |
| IWG | Inches of water gauge |
| Dip Tube | Long plastic tubes that fit into the inlet of a water heater to direct incoming cold water to the bottom of the heater |
| Entropy | Unavailability of a system's thermal energy for conversion into mechanical work |
| Enthalpy | Total heat content in a system; internal energy + pressure*volume |
| First Law Efficiency | Based upon the First Law of Thermodynamics; based on the actual energy use and not taking into account things like excess energy |
| Second Law Efficiency | Based on the Second Law of Thermodynamics; instead of energy, uses free energy within the system |
| Saturation Temperature/Pressure | Point at which a liquid reaches its boiling point to turn to vapor |
| Steam Turbine Internal Efficiency | Conversion of input energy into output work without dissipating energy |
| Compressed Liquid | Is a fluid under mechanical or thermodynamics conditions that force it to be a liquid |
| Saturated Liquid | A liquid whose temperature and pressure are such that any decrease in pressure without changes in temperature which causes it to boil |
| Superheated Liquid | Liquid water under pressure at temperatures between the usual boiling point and the critical temperature |
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