Lecture_3 - ME 2322 Engineering Thermodynamics I Lecture...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
ME 2322 Engineering Thermodynamics I Lecture 03, 1/20/11 Prof. Zhaoming He
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 1 Introduction and Basic concepts • Concepts – Dimension and units – System and surroundings – Closed system (control mass) and open system (control volume) – properties and state – state equilibrium and postulate – process and cycle • Review concepts of temperature and Pressure • Introduce a systematic problem-solving technique.
Background image of page 2
Static Fluid Pressure Calculation Choose reference point O (known pressure P 1 ) Measure distance Δ z from reference point to the point of interest of pressure Apply formula (regardless of x,y) Δ z is “+” if in gravitational direction Δ z is “–” if against gravitational direction) z g P P + = ρ 1 2 Z is gravitational direction O
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Pascal’s Law • The pressure applied to a confined fluid increases the pressure throughout by the same amount • Two hydraulic cylinders of different areas could be connected to exert a greater force 2 1 2 1 F F P P =
Background image of page 4
Multiple Fluids For the multiple immiscible fluids of different densities, the pressure at interfaces between the fluids is continuous (no discontinuous jump) Pressure at 1 (bottom of fluid 1) can be calculated by multiple steps of accumulation of multiple fluid region (starting from position with known pressure) P1 P2 P3 3 3 3 2 2 1 1 P gh gh gh P atm = + + + ρ ρ 1 1 1 gh P P atm + = 2 2 1 2 gh P P + = 3 3 2 3 gh P P + =
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1-87 A multifluid container is connected to a U-tube, as shown in the figure. For the given specific gravities and fluid column heights, determine the gage pressure at A. Also determine the height of a mercury column that would create the same pressure at A. Glycerin
Background image of page 6
Barometer Atmospheric pressure is measured by inverting a liquid-filled tube in a container that is open to atmosphere P atm = ρ gh h=760 mmHg Stardard P atm =101325 kPa at sea level and 0°C at standard g – P atm changes with elevation
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1. Problem statement: collect key information, understand problem and objective 2. Schematic: sketch physical system, list key features, relationship: properties, process, energy and mass interaction 3. Assumptions and approximations : simplify the problem by assume reasonable necessary values, relationship 4. Physical laws, properties: conservation of mass, energy 5. Analysis, calculations: determine unknowns, pay attention to unit 6. Reasoning, verification, and discussion: check the results
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 28

Lecture_3 - ME 2322 Engineering Thermodynamics I Lecture...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online