Heat Engine | Working, Efficiency [Brief Explanation]

What is a Heat engine? A heat engine is a device which operates in a cyclic process to generate work from the supplied heat. Below diagram shows working of a heat engine Where: Th: Temperature of source Tc: Temperature of sink Qh: Heat supplied to the engine Qc: Heat rejected by the engine W: Work… Read More »

Second Law of Thermodynamics [Kelvin-Plank & Clausius Statement]

Second law of thermodynamics Second law of thermodynamics is perhaps one of the most important law of science (more specifically physics) because it tells us about the directional constraint of a process. Here one question may arise. What is a directional constraint? We all know that all-natural (and artificial) processes always proceed spontaneously towards equilibrium… Read More »

First Law of Thermodynamics [Open and Closed Systems]

First law of thermodynamics The first law of thermodynamics states that: The algebraic sum of net heat and work interactions between a system and its surrounding in a thermodynamic cycle is zero Mathematically For a cyclic process ΣQ = ΣW Where: Q = Heat interaction W = Work interaction For a finite non-cyclic process Q1-2… Read More »

Thermodynamic Process and Cycle | Quasi Static Process

Thermodynamic process Any change in the thermodynamic state of a system is called a thermodynamic process. For example: In the above graph process 1-2 is a thermodynamic process. Thermodynamic cycle Any series of thermodynamic state change in which the initial and final states of the system (thermodynamic system) are same is called a thermodynamic cycle.… Read More »

Thermodynamic Concept of Energy

We can understand Thermodynamic concept of energy with the help of following diagram.   Energy in storage is sometimes also referred as Internal energy. It is a point function. Energy in transit is a path function. Different types of work transfer Displacement or P*dV work Paddle wheel work Flow work Shaft work Also read: What… Read More »

Thermodynamic Equilibrium [A Brief Explanation]

Thermodynamic equilibrium A system can achieve Thermodynamic equilibrium in the following two ways. When the system is isolated from the surrounding through an adiabatic wall When the system has same thermodynamic state as that of surrounding. Such a system is called to be in dead state. For being in thermodynamic equilibrium, a system has to… Read More »

Thermodynamic State | Gibbs’ Phase Rule | Thermodynamic Equilibrium

Thermodynamic state A system will be called in a particular thermodynamic state if it satisfies both the below mentioned criteria. All the thermodynamic properties of the system are uniform throughout the system All the thermodynamic properties of the system remain constant with respect to the time (at least for that moment) Note: all the properties… Read More »

Thermodynamic Properties : Extensive and Intensive

Thermodynamic properties Thermodynamic properties are the characteristics (identifiable and observable) of a system by which it can be specified. For example: mass, volume, temperature, pressure etc. Thermodynamic properties can be divided into two groups Extensive properties Intensive properties Now let us understand each types of property in detail. Extensive thermodynamic property Extensive properties are those… Read More »

Macroscopic and Microscopic Approach to Study Thermodynamics

What are different approaches to study thermodynamics? We can understand thermodynamics from two viewpoints (or approaches). One is microscopic and another is macroscopic. Let us discuss each of them in detail. However, in Mechanical Engineering we only consider macroscopic approach. Macroscopic (or Classical) view In macroscopic approach we fix our attention to certain quantity of… Read More »