Determination of Safe Operating Conditions for Non-gasketed Flange Joint under Combined Internal Pressure and Temperatur
- PDF / 519,922 Bytes
- 12 Pages / 595.276 x 841.89 pts (A4) Page_size
- 40 Downloads / 185 Views
Springer 2006
Determination of safe operating conditions for non-gasketed flange joint under combined internal pressure and temperature MUHAMMAD ABID Faculty of Mechanical Engineering, GIK Institute of Engineering Sciences and Technology, Topi, NWFP, Pakistan (E-mail: [email protected])
Abstract. Performance of a flange joint is characterised mainly due to its ‘strength’ and ‘sealing capability’. A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. However, with the advent of new technological trends for high temperature and pressure applications, an increased demand for analysis is recognised. The effect of steady state thermal loading is a well recognised problem and makes the problem more complex under combined application of internal pressure and temperature. The present design codes do not address the effects of temperature on the structural integrity and sealing ability. To investigate, joint strength and sealing capability under combined internal pressure and different steady state thermal loading, a 3D nonlinear finite element analysis of non-gasketed flange joint is carried out and its behaviour is discussed. To determine the safe operating conditions or actual joint load capacity, the joint is further analyzed for different internal pressures and temperatures. In addition, effect of coefficient of thermal expansion of different flange joint component material is discussed and importance is highlighted. Key words: non-gasketed, combined, bolt up, operating, temperature, sealing, strength
Notations: m: Poisson’s ratio; a: Coefficient of thermal expansion; rbol: Stefan–Boltzman constant; eem: Emissivity; E: Young’s modulus of elasticity; K: Thermal conductivity; hcon: Convection heat transfer coefficient; h: Combined convection and radiation heat transfer coefficient; T: Applied temperature; Tamb: Ambient air temperature
1. Introduction Different types of flange joints evolved over the centuries and were perfectly adequate for their duties at low pressure and temperature but high pressure and temperature applications led to sealing problems. Leakages (small and large) in flange joints, is a continued significant safety concern both in terms of human life, environmental effect and cost. With the rapid advancement in technology for high pressure and temperature applications, trends are changing. A flange joint must have adequate mechanical strength and good leak tightness, therefore it is important to evaluate the integrity and sealing performance at actual operating conditions. Available design rules (BS, 1989; ASME, 1998] for flange joints are mainly concerned with the strength of the flanges and do not sufficiently consider for their sealing. In addition these do not address the effect of temperature on integrity and sealing performance. Nongasketed flange joints are considered as an alternative due to the ‘static mode of load’ during both the bolt up and internal pressure applications (Webjo¨rn, 1967, 1985; Abid, 2000; Abid et al., 2000; Abid and N
Data Loading...
