Читать книгу Hydraulic Fluid Power - Andrea Vacca - Страница 52

The fundamental principles of fluid power are closely related to those of fluid mechanics: the basic relations used to analyze the operation of a fluid power system originate from the fundamental equations of fluid mechanics.

The basic concepts of hydraulic systems are usually presented with the simplified assumption of stationary conditions. This allows deriving very simple equations for the working fluid, which are particularly suitable to describe the functioning of even complex system layout architectures. This chapter describes how these simplified equations are derived from the classic equations of fluid mechanics of general validity. Readers with basic knowledge of fluid mechanics will appreciate and understand the derivation of these basic equations used throughout this book.

Knowledge of the tools used to perform a dynamic analysis is not necessary to understand the basic operation of a hydraulic circuit. This dynamic analysis becomes necessary when studying the system behavior during transients, for example, a sudden variation of the external load or the commutation of the system from one state to another (such as the sudden change in the commanded position of a hydraulic control valve). Some basic concepts pertaining to the dynamic behavior of hydraulic control systems during transients will be introduced in Chapter 5.