Lämpösiirtokerrointa

Lämpösiirtokerrointa, known in English as the heat transfer coefficient, is a fundamental concept in thermodynamics and heat transfer. It quantifies the rate at which heat is transferred across a boundary between a fluid and a solid surface. The value of the heat transfer coefficient depends on various factors, including the properties of the fluid (such as viscosity, thermal conductivity, and density), the flow regime (laminar or turbulent), and the geometry of the surface.

The heat transfer coefficient is typically denoted by the symbol 'h' and has units of watts per square meter per kelvin (W/m²K) or BTU per hour per square foot per degree Fahrenheit (BTU/h·ft²·°F). A higher heat transfer coefficient indicates a more efficient transfer of heat. For instance, in forced convection, where a fluid is moved across a surface by external means like a fan or pump, the heat transfer coefficient is generally much higher than in natural convection, where fluid movement is driven by density differences due to temperature variations.

This parameter is crucial in the design and analysis of many engineering applications, including heat exchangers, cooling systems, and building insulation. By understanding and calculating the heat transfer coefficient, engineers can predict and control the thermal performance of various systems, ensuring they operate efficiently and safely.