Heat transfer - Ceballos Romero Enrique

6 Glossary - Week 5 terms

Density

Noun

The density (more precisely, the volumetric mass density; also known as specific mass), of a substance is its mass per unit volume.

Example: The density of air is 1.2 kilograms per cubic metre.

es: Densidad

Heat sinks

Noun

Is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light-emitting diodes (LEDs), where the heat dissipation ability of the component itself is insufficient to moderate its temperature.

Example: Passive heat sinks are those that don’t rely on forced air flow (fans) and are considered more reliable than active solutions. A good example is a heat sink that doubles as the device enclosure. Heat is moved from one or more heat generating components to one or more enclosure walls. These walls typically have a fin array exposed to the outside ambient air.

es: Disipadores de calor

Specific heat

noun

Specific heat, the quantity of heat required to raise the temperature of one gram of a substance by one Celsius degree. The units of specific heat are usually calories or joules per gram per Celsius degree.

Example: The specific heat of water is 1 calorie (or 4,186 joules) per gram per Celsius degree

es: Calor especifico

Steady state

Noun

Steady state is a situation in which all state variables are constant in spite of ongoing processes that strive to change them. For an entire system to be at steady state, i.e. for all state variables of a system to be constant, there must be a flow through the system (compare mass balance)

Example: The case of a bathtub with the tap open but without the bottom plug after a certain time the water flows in and out at the same rate, so the water level (the state variable being Volume) stabilizes and the system is at steady state.

es: estado estable

Thermal expansion coefficient

Noun

The coefficient of thermal expansion describes how the size of an object changes with a change in temperature. Specifically, it measures the fractional change in size per degree change in temperature at a constant pressure, such that lower coefficients describe lower propensity for change in size. Several types of coefficients have been developed: volumetric, area, and linear.

Example: Railroad tracks and bridges, have expansion joints to allow them to freely expand and contract with temperature changes.

es: Coeficiente de expansión térmica

Young´s modulus

noun

The Young modulus, or the modulus of elasticity in tension or compression, is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied lengthwise.

Example: In the case of a metal rod that after being stretched or compressed lengthwise returns to its original length.

es: El módulo de Young