Natural Convection Inside Vertical Isothermal Ducts of Constant Arbitrary Cross Section
نویسندگان
چکیده
A model for steady laminar natural convection inside vertical, arbitrarily shaped isothermal ducts of constant cross section is presented. The model is based on a combination of asymptotic solutions for fully developed and developing, boundary-layer ow. The fully developed asymptote model utilizes forced convection, internal ow modeling techniques, and an approximate model is presented, which is valid for a wide range of duct shapes and aspect ratios. Themodel is validatedusing experimental dataandnumerical results from the literature for a variety of duct shapes, including the triangle, square, circle, rectangle and the special case of parallel plates. The model is in good agreement with all of the data, with an rms percent difference of 10% or less in most cases.
منابع مشابه
Natural Convection Heat Transfer From Horizontal Cylinders in a Vertical Arra Confined Between Parallel Walls
Laminar natural convection from an array of horizontal isothermal cylinders confined between two vertical walls, at low Rayleigh numbers, is investigated by theoretical and numerical methods. The height of the walls is kept constant, however, number of the cylinders and their spacing, the distance between the walls and Rayleigh number have been varied. The optimal spacing (confining walls) and ...
متن کاملTransient Natural Convection Flow on an Isothermal Vertical Wall at High Prandtl Numbers: Second-Order Approximation
The method of matched asymptotic expansions, which has been used in previous studies of steady natural convection flow, is extended here to transient natural convection flow at high Prandtl number (Pr). Second-order expansion solutions, valid for large Prandtl numbers, are presented for the transient natural convection flow near a vertical surface which undergoes a step change in temperature. T...
متن کاملMeasurements of temperature profiles in gases by laser beam deflection
2014 The determination of temperature profiles in gases is based on the light beam deflection due to the refractive index gradient induced by a temperature gradient at constant pressure. The geometry considered for the system is a cylinder of arbitrary section characterized by isothermal generative lines. A parameter estimation method and a parabolical trajectory method are considered to treat ...
متن کاملNatural Convection Heat Transfer within Octagonal Enclosure
The problem of steady, laminar and incompressible natural convection flow in an octagonalenclosure was studied. In this investigation, two horizontal walls were maintained at a constant hightemperature, two vertical walls were kept at a constant low temperature and all inclined walls wereconsidered adiabatic. The enclosure was assumed to be filled with a Bousinessq fluid. The studyincludes comp...
متن کاملThermal Development for Ducts of Arbitrary Cross Sections by Boundary-Fitted Coordinate Transformation Method
The non-orthogonal boundary-fitted coordinate transformation method is applied to the solution of steady three-dimensional momentum and energy equations in laminar flow to obtain temperature field and Nusselt numbers in the thermal entry region of straight ducts of different cross sectional geometries. The conservation equations originally written in Cartesian coordinates are parabolized in the...
متن کامل