The First Law's Applicability To Open Systems

The first law of thermodynamics is a universal law that applies to both open and closed systems. It is a formulation of the law of conservation of energy, which states that energy cannot be created or destroyed, only transformed from one form to another. In an open system, both energy and mass transfer takes place, and the law of conservation of energy and mass must be considered.

The first law of thermodynamics distinguishes two principal forms of energy transfer: heat and thermodynamic work. It also defines the internal energy of a system, which is an extensive property that accounts for the balance of heat and work in the system.

For open systems, the first law of thermodynamics can be interpreted as follows: if shaft work and heat are transferred across the system boundary to or from a fluid moving through an open system, the fluid will generally undergo changes in internal energy, energy associated with the acting pressure at the system boundary, gravitational energy, and kinetic energy.

The first law of thermodynamics is a universal law

The first law of thermodynamics is a formulation of the law of conservation of energy in the context of thermodynamic processes. It distinguishes two principal forms of energy transfer, heat and thermodynamic work, that modify a thermodynamic system containing a constant amount of matter. The law also defines the internal energy of a system, an extensive property that accounts for the balance of heat and work in the system.

In an open system, both energy and mass transfer takes place. This means that both the law of conservation of energy and the law of conservation of mass must be considered. For example, in a jet engine, which is an open system, the rate at which energy flows into the system will be equal to the rate at which energy flows out of the system.

The first law of thermodynamics can be applied to a resistor carrying a current. In this case, the quantities ∆Q, ∆U, and ∆W represent changes in heat, internal energy, and work done by the system, respectively.

It applies to both open and closed systems

The first law of thermodynamics applies to both open and closed systems. This law is a universal law and a formulation of the law of conservation of energy in the context of thermodynamic processes. It distinguishes between two principal forms of energy transfer: heat and thermodynamic work, which modify a thermodynamic system containing a constant amount of matter.

In an open system, both energy and mass transfer takes place, and thus, the law of conservation of energy and mass is considered. The rate at which energy enters an open system will be equal to the rate at which energy exits the system. This is known as the principle of conservation of energy.

For example, consider a turbine, which is an open system. The only energy entering the system is the enthalpy of the inlet stream. Energy exits the system as shaft work and also with the outlet stream. The first law states that the rate at which energy enters the system must equal the rate at which energy exits the system.

The first law of thermodynamics can be applied to a wide range of systems, from a jet engine of an aircraft to turbines, boilers, and pumps in large-scale power generation plants.

In an open system, both energy and mass transfer takes place

The first law of thermodynamics is a universal law that applies to both open and closed systems. This law is a formulation of the law of conservation of energy in the context of thermodynamic processes. It distinguishes between two principal forms of energy transfer: heat and thermodynamic work. The law also defines the internal energy of a system, which is an extensive property used to account for the balance of heat and work in the system.

In an open system, the internal energy is a function of the state, and the change in internal energy during a process depends only on the initial and final states of the system, not on the path between them. The rate at which energy enters an open system must be equal to the rate at which energy exits the system. This principle is in accordance with the law of conservation of energy.

Examples of open systems include a thrown ball experiencing air resistance, a chemical reaction taking place inside a container over an open flame, and a jet engine of an aircraft.

The law distinguishes two principal forms of energy transfer: heat and thermodynamic work

The first law of thermodynamics is a formulation of the law of conservation of energy in the context of thermodynamic processes. It distinguishes two principal forms of energy transfer: heat and thermodynamic work. These two forms of energy transfer modify a thermodynamic system containing a constant amount of matter. The law also defines the internal energy of a system, an extensive property that accounts for the balance of heat and work in the system.

Heat and work are the two ways of supplying or removing energy from a system. Work is done when a force acts over a distance. For instance, the external force of an external pressure supplied by the surroundings, multiplied by the corresponding area along the boundary of the system. The differential mechanical work resulting from a differential displacement is given by:

> dW = - pext(Axdx + Aydy + Azdz)

Where the external pressure is constant along the boundary of the system. Ax is the area normal to the x-coordinate that is being displaced, and so forth. The minus sign indicates that work is positive if the displacement is negative (i.e. an external force compresses the system).

Heat, on the other hand, is the energy transferred between a system and its surroundings by virtue of a temperature difference. It is defined as energy transferred by thermal contact with a reservoir, which has a temperature and is generally so large that additions or removals of heat do not alter its temperature.

The first law of thermodynamics applies to both open and closed systems. An open system allows mass and energy to flow into or out of the system. In such a system, both the law of conservation of energy and mass are considered. For example, the jet engine of an aircraft is an open system. The turbines, boilers, and pumps in large-scale power generation plants are also open systems.

In an open system, the rate at which energy flows is given in kJ/sec or kW. The rate of mechanical energy output, or power, is also measured in kW. The unit "W" stands for Watt.

The first law states that the rate at which energy flows into a system must equal the rate at which energy flows out of the system. In mathematical terms:

> m h_in = m h_out + W_out

Where m is the mass flow rate, h is the enthalpy, and W is the rate of shaft work or power.

The law also defines the internal energy of a system

The first law of thermodynamics is a formulation of the law of conservation of energy in the context of thermodynamic processes. The law also defines the internal energy of a system, which is an extensive property that accounts for the balance of heat and work in the system.

Internal energy is a mathematical abstraction that keeps track of the changes in energy within the system. It is a property of the system, while work and heat describe the process. Work and heat are said to be path-dependent, meaning they depend on the initial and final states of the system, rather than the path taken between them.

The internal energy of a system can be calculated using the equation:

ΔU = Q - W

Where:

• ΔU is the change in internal energy
• Q is the quantity of heat supplied to the system from its surroundings
• W is the thermodynamic work done on or by the system

The first law of thermodynamics can be applied to both open and closed systems. In an open system, both energy and mass transfer takes place, and both the law of conservation of energy and mass are considered.

For example, consider a turbine in a steady-state open system. The turbine converts the enthalpy of the incoming stream into shaft power, and the first law states that the rate at which energy flows into the system must equal the rate at which energy flows out. In mathematical terms:

M * h_in = m * h_out + W_out

Where:

• M is the mass flow rate
• H_in is the enthalpy of the inlet stream
• H_out is the enthalpy of the outlet stream
• W_out is the shaft work done by the turbine

In summary, the first law of thermodynamics defines the internal energy of a system as the balance of heat and work within the system, and this law applies to both open and closed systems.

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