0
What else can I help you with?
Differences between fixed displacement pump and variable displacement pump?
the main difference between them is the way that energy is added to the fluid to be converted to pressure increase. In dynamic pumps, energy is added to the fluid continuously through the rotary motion of the blades. These rotating blades raise the momentum of fluid and the momentum then is converted to pressure energy through diffuser in pump outlet. In positive displacement pumps, the energy is added periodically to the fluid. the pump has reciprocating motion by pistons for example. When the fluid enters the pump through valves, the reciprocating piston begins to press the fluid resulting in going out of the pump with pressure rise.
Difference between bar and barg?
The 'g' added on to bar means 'gauge', as opposed to bara, meaning 'absolute'. The 'zero' of a normal gauge is normally set at atmospheric pressure (things like tire pressure gauges, water gauges etc.) These gauges will read as "10 bar" but really mean that the absolute pressure is 10 bar + atmospheric pressure (~1.01325 bar). Some gauges however are absolute gauges. These might include weather gauges, or gauges on closed processes. bara = barg + atmospheric pressure
Hydrotesting procedure of Shell and Tube heat exchanger?
The hydro-testing procedure of a shell and tube heat exchanger requires you to fill the shell and tubing with water that had a color dye added to it. Then, raise the internal pressure by 1.5 times the operating pressure suggested by the manufacturer. If there are any cracks in the vessel, the water will be forced out through the cracks.
Is the expansion of superheated steam isothermal?
Expansion of steam in either the saturated or superheated state is generally not isothermal. When steam expands from a high pressure to a lower pressure the temperature will be reduced, unless energy is added during the process. When steam expands in an engine such as a steam turbine, the temperature reduction is greater than during free expansion
Why cavitation will occur in Centrifugal Pumps and not in displacement pumps?
Cavitation occurs when the pressure on a liquid drops below the vapor pressure for the liquid or when gas is otherwise introduced to a pump such that it disrupts the flow of the liquid through the pump.Positive displacement pumps trap a quantity of liquid (or gas) and then increase the pressure by pushing (displacing) it into the discharge pipe. External pressure pushes the liquid into the pump chamber which then is made smaller before the pump chamber discharges its contents. If any gas enters the pump chamber along with a liquid it is simply compressed along with the liquid. Positive displacement pumps work just fine with both gases and liquids - although when gases are being compressed it is usually necessary to cool the pump chamber which heats up quite a bit during the almost adiabatic compression step of the pump. Cavitation does not occur in part because the pressure in the pump chamber is almost completely uniform. If the compression chamber drops below the vapor pressure of a liquid being pushed into it, the external pressure will continue to push the liquid in, then when the pump begins to decrease the volume, the valve allowing the liquid to enter will close and the volume of the contents is decreased until the pressure rises back above the vapor pressure of the liquid and it condenses in the pump chamber.A centrifugal pump uses a rotating impeller to increase the pressure and flow rate of a fluid. In centrifugal pumps, pressure is added by increasing the kinetic energy of the liquid and then, in essence, "throwing" the liquid into the discharge pipe where the higher kinetic energy liquid pushes on the liquid ahead of it to increase pressure. As the impeller moves through the liquid being pumped, it pushes on the liquid ahead of it, imparting additional kinetic energy to it. The liquid behind the impeller, however, actually experiences a little bit of a drop in pressure as the impeller tries to move away from it. Because liquids are fairly incompressible, this usually does not create any problem and the internal pressure of the liquid is sufficient to keep it in contact with the backside of the impeller. If the drop in pressure is low enough that the pressure drops below the vapor pressure of the liquid at the temperature present in the pump, the liquid will begin to vaporize. Once gas is present in the pump, it begins to cavitate - the liquid separates from the back of the impeller - especially near the tips. For this reason, introducing air or other gas into the liquid can cause cavitation, even if the pressure never drops below the vapor pressure of the liquid being pumped. This is also why centrifugal pumps are usually "primed" prior to being started up - to get all, or at least most, of the gas out of the line so that the pump won't cavitate.
What happens when to a gas when heat is added?
If under constant pressure, it expands, but if it has a fixed volume, the pressure will increase. These are related, the formula is (pressure x volume = constant x temperature), or p x v = R x T. T has to be absolute ie degrees kelvin
Why dual combustion cycle is called as limited pressure cycle?
In dual combustion cycle heat is added at constant volume which increases the efficiency of cycle, whereas heat addition at constant pressure limits the maximum pressure of the cycle.
Dual combustion cycle?
From Wikipedia, the free encyclopedia Dual Combustion Cycle (also known as the limited pressure or mixed cycle, Seiliger cycle or Sabathe cycle) is a thermal cycle that is a combination of the Otto cycle and the Diesel cycle. Heat is added partly at constant volume and partly at constant pressure, the advantage of which is that more time is available for the fuel to completely combust. Because of lagging characteristics of fuel this cycle is invariably used for diesel and hot spot ignition engines. The dual cycle consists of following operations: # Adiabatic compression # Addition of heat at constant volume. # Addition of heat at constant pressure. # Adiabatic expansion. # Rejection of heat at constant volume.
According to Boyle's Law if the volume and temperature of a gas in a closed container remain constantwhat happens to the gas's pressure?
It goes up.
Why the molar specific heat at constant pressure is larger than the molar specific heat at constant volume?
The specific heat at constant pressure is larger than the molar specific heat at constant volume because if heat is added to a system it not only heats up but expands in volume. Therefore the system is doing work against the external pressure and the heat is not only stored as kinetic and potential energy but is also required to perform work. In general more heat can be stored in a system at constant pressure than one at constant volume. The specific heat at constant pressure is larger than the molar specific heat at constant volume because if heat is added to a system it not only heats up but expands in volume. Therefore the system is doing work against the external pressure and the heat is not only stored as kinetic and potential energy but is also required to perform work. In general more heat can be stored in a system at constant pressure than one at constant volume.
Why does pumping air into a tire at a constant temperature increase the pressure?
When air is pumped into a tire at a constant temperature, the pressure increases because the volume of the tire decreases as more air is added. This causes the air molecules to be more tightly packed together, resulting in higher pressure within the tire.
What is the difference between Charles' Law and Boyle's Law?
Gases have diverse properties tat we can observe with our senses. These properties include gas pressure, temperature (T), mass, and the volume that contains the gas. Close scientific observation has confirmed that these variables are related to one another and that the values of these properties can determine the states of the gas. Boyle's law states that at a constant temperature the volume of a gas is inversely proportional to the pressure while Charles law states that the relationship between temperature and volume are proportional to one another.Boyle's Law states that the product of the pressure and volume for a gas is a constant for a fixed amount of gas at a fixed temperature. The mathematical relationship of Boyle's law is given as PV=k (P= pressure, V= volume, k= constant). When the pressure of the gas was increased, the volume of the gas decreased. This can be seen when, as more weights are added onto a piston, the pressure increases while the volume decreases leaving less room for the particles to move around. So if the volume was 10 Liters and the pressure was 1 atm., the value of k was 10 L atm. This value for k is the same even after a 50 Kg. weight is added changing the volume to 8.39 Liters and the pressure to 1.18 atm.Another law that states the relationship between temperature and volume when pressure is constant is Charles's law. The mathematical relationship is V/T=b (V= volume, T= temperature, b= a constant). As volume increases so does the temperature. The initial value for b (the constant) before the heating of the gas inside the piston chamber was around 0.017 L / K. This value was also the same or constant after increasing the temperature of the gas inside the piston by 10 degrees Celsius. Initially, for temperature of 25o C or 298 K the volume was 5 liters (pressure constant) and at 35o C or 308 K, the volume changed to 5.17 Liters but when you substitute these values into the equation V/T= b, b is the same value. Thus, even though the values change in both laws, the constant remains the same.The constant in Charles law depends on the quantity of gas and the pressure. The ratio of volume to temperature for any set of volume - temperature values always equals the same. In Boyle's law, the constant for different gases can be determined by finding out the volumes and pressures.
What is the enthalpy equation used to calculate the change in heat energy of a system at constant pressure?
The enthalpy equation used to calculate the change in heat energy of a system at constant pressure is H q PV, where H is the change in enthalpy, q is the heat added or removed from the system, P is the pressure, and V is the change in volume.
What is true about an isochoric process?
Temperature is constant.ΔU = 0 W=Q
Will changing the volume of a container filled with gas change the mass of the gas?
No, changing the volume of a container filled with gas will not change the mass of the gas. The mass of the gas remains constant unless gas is added or removed from the container. Changes in volume only affect the pressure and density of the gas.
What isothermal process?
Isothermal process is a process in which change in pressure and volume takes place at a constant temperature.
What happens to the pressure of a container at a constant pressure and temperature when gas particles are added?
The pressure of the container would increase because adding more gas particles increases the number of collisions with the walls of the container. This leads to an increase in the force exerted by the gas on the walls, resulting in a higher pressure.
