solving a heat transfer problem

... 18 22 4 The heat flux, q, is a heat rate per unit area and can be expressed as Q /A, where A is an appropriate area Figure 1. 3 An analogy for the three modes of heat transfer 11 ... Heat transfer People have always understood... 513 References 517 Contents x IV Thermal Radiation Heat Transfer 10 Radiative heat transfer 10 .1 The problem of radiative exchange ... 01-04-0249 A HEAT TRANSFER TEXTBOOK THIRD EDITION John H. Lienhard IV / John H. Lienhard V A Heat Transfer Textbook  Lienhard & Lienhard A Heat Transfer Textbook A Heat Transfer Textbook...

Ngày tải lên: 07/08/2014, 10:20

... This value is of approximately the same size as h for natural convection into a gas at such temperatures Thus, the heat transfer by thermal radiation... weather data to estimate heating and ... and the overall heat transfer coefficient §2.3 Table 2.1 Some typical interfacial conductances for normal surface finishes and moderate contact pressures (about 1 to 10 atm). Air gaps not evacuated ... roughness is always present, a typical plane of contact will always include tiny air gaps as shown in Fig. 2.10 §2.3 Thermal resistance and the electrical analogy 65 Figure 2.10 Heat transfer through...

Ngày tải lên: 07/08/2014, 10:20

... approximations can be made: • The membrane surface has been blackened so that it ab- sorbs all radiation that falls on it • The radiant heat flux is much larger than the heat lost from the membrane by ... conduction, thermal resistance, and the overall heat transfer coefficient 2.39 Layers of equal thickness of spruce and pitch pine are lami- nated to make an insulating material. How should the lamina- tions ... V. Madhusudana. Thermal Contact Conductance. Springer- Verlag, New York, 1996. [2.5] R. A. Parsons, editor. 1993 ASHRAE Handbook—Fundamentals. American Society of Heating, Refrigerating, and Air-Conditioning...

Ngày tải lên: 07/08/2014, 10:20

... Evaluate the heat transfer, pressure drop, and cost of various exchanger configurations that appear reasonable for the application This is usually done with large-scale computer programs that ... the same way as we derived the LMTD. Each configuration must be analyzed separately and the results are generally more compli- cated than eqn. (3.13). This task was undertaken on an ad hoc basis ... 72.78 ◦ C Example 3.6 Suppose that we had the same kind of exchanger as we considered in Example 3.5, but that the area remained unspecified as a design variable. Then calculate the area that would...

Ngày tải lên: 07/08/2014, 10:20

... 148 Analysis of heat conduction and some steady one-dimensional problems §4.2 Figure 4.3 A two-dimensional slab maintained at a constant temperature on the sides and subjected to a sinusoidal varia- ... is cooled or heated through a heat transfer coefficient, h, by the ambient fluid The heat transfer coefficient will be assumed uniform, although (as... parabola But as small as the difference ... situation was given in eqn. (1.21). [A partic- ular solution was also written in eqn. (1.22).] 146 Analysis of heat conduction and some steady one-dimensional problems §4.2 Separation of variables:...

Ngày tải lên: 07/08/2014, 10:20

... appears in the lumped-capacity solution (Chapter 1) Thus, h(P L) kA/L is like UA Cmin is like hA ρcV /t In each case a convective heat rate is compared with a heat rate that characterizes ... A thin rod is anchored at a wall at T... insulated tips that would give the same temperature gradient at each wall Base the correction on these values of mL 4.23 A fin of triangular axial ... the capacity of a system;... 4.33 Heat transfer is augmented, in a particular heat exchanger, with a field of 0.007 m diameter fins protruding 0.02 m into a flow The fins are arranged...

Ngày tải lên: 07/08/2014, 10:20

... t/T can be viewed as t T = hk(V /A) t ρc(V /A) 2 k = h(V /A) k · αt (V /A) 2 = Bi Fo (5.7) Electrical and mechanical analogies to the lumped-thermal-capacity problem The term capacitance is adapted ... briefly at the dimensional analysis of transient con- duction in general and of lumped-capacity systems in particular. Dimensional analysis of transient heat conduction We first consider a fairly ... 4.39 The heat transfer coefficient between a cool surface and a satu- rated vapor, when the vapor condenses in a film on the surface, depends on the liquid density and specific heat, the tempera- ture...

Ngày tải lên: 07/08/2014, 10:20

... superheated to a temperature somewhat above its boiling point, a small gas or vapor cavity in that liquid will grow (That is what happens in the superheated water at the bottom of a teakettle.) ... only one half of the area We illustrate... not the analytical solution is already available in a heat conduction text or in other published literature • Solve the problem (a) Analytically (b) ... been cataloged by Schneider [5.5]. Analytical solutions are available for hundreds more problems, and any reader who is faced with a complex heat conduction calculation should consult the literature...

Ngày tải lên: 07/08/2014, 10:20

... 5.3 A body of known volume and surface area is immersed in a bath whose temperature is varying sinusoidally with a frequency ω about an average value The heat transfer coefficient is known and ... thick and in square is held at 100◦ F on one in by in surface The opposing in by in surface is adiabatic for in and 90◦ F for inch The remaining surfaces are adiabatic Find the rate of heat transfer ... inner arc, r = ri , and an adiabatic outer arc, r = ro The flat surface along θ = is isothermal at T1 , and the flat surface along θ = π /2 is isothermal at T2 Show that the shape factor is S = (2/π...

Ngày tải lên: 07/08/2014, 10:20

... m in length and ½ m in width Find the average heat transfer coefficient and the total heat transferred What are h, δt , and δ at the trailing edge? Heat transfer coefficient for laminar, incompressible ... Boundary layer with an unheated starting length Figure 6.16 shows a b.l with a heated region that starts at a distance x0 from the leading edge The heat transfer in this instance is easily obtained ... boundary layers We first ask what dimensional analysis reveals about heat transfer in the laminar b.l We know by now that the dimensional functional equation for the heat transfer coefficient, h, should...

Ngày tải lên: 07/08/2014, 10:20

... very near wall and in the near wall region the convective terms are again negligible This means that ∂q/∂y near the wall, so that the heat flux is constant in y and equal to the wall heat flux: ... transitional value §6.8 Heat transfer in turbulent boundary layers A correlation for laminar, transitional, and turbulent flow A problem with the two preceding relations is that they not really deal ... outer walls are at 27◦ F Find the heat loss, conservatively assuming that the east and west faces have the same h as the north, south, and top faces Estimate U for the walls 6.27 A ft-square slab...

Ngày tải lên: 07/08/2014, 10:20

... string may contain alphabetic characters as well as numeric characters and may contain other special characters such as punctuation marks and arithmetic symbols Printing both exact literal characters ... In addition, a parameter may be used in some places where a variable may not be used Examples are indicating the size of a static array and the values selected by a case statement program parameter_example ... constant makes a program more readable It is easy to forget what role an unnamed constant plays in a program Another important reason for using a parameter declaration is that the program can be...

Ngày tải lên: 24/10/2014, 20:49

... in another league If training programs were animals, HFT for Arms would be a pit bull- a tough sumbitch by any standard- while Total-Body HFT is Sasquatch The end results are as unique as a fingerprint ... use a variety of hand fifth week Rather than taking the entire week positions-neutral (palms facing each other) off from training, you scale back the weights and overhand (palms down) as well as ... said about being as handy Start with what looks like a ridiculously brief as possible, it requires a detailed answer light weight, and try a few reps, focusing on your balance and form Go up a...

Ngày tải lên: 14/03/2014, 23:20

... vertical than you can with a traditional squat, and thus increase your range of motion UP: Return to the starting position and exhale 242 VARIATIONS: 2» 1» FAST PARTIAL FRONT SQUAT SUPRAMAXIMAL ... Get Big, Phases and 3; Get Even Bigger, HFT for Arms and Total-Body HFT; Get Strong, Phases lA, 2A , and 3A; Get Even Stronger, Phases lA, 2A, and 3A; Get Lean, Phases lA, 2A, and 3A HOW TO DO ... challenge here varies with the size of the you in place You can medicine ball (You WHERE IT IS: Get Big , Phases lA, 2A, and use any Swiss ball you have available, as long can also use a basketball...

Ngày tải lên: 14/03/2014, 23:20

... in a few categories of with each meal and snack A serving of fruit is food that you'll typically eat Soon you'll be an apple, banana, orange, peach, or pear, or a able to plan and prepare meals ... HARDGAINERS ONLY fat more easily than muscle True hard gainers-as opposed to guys 100-150 1/2 ba nana* 10 grams grams 150-200 banana 20 grams grams 200+ ba nana 30 gram s 10 grams who just haven't ... include bloating, diar- happens to be a naturally occurring trans fatty rhea, and gas I mean really, really, really bad acid, found in meat and cheese The ones you gas So avoid sugar alcohols, and get...

Ngày tải lên: 22/03/2014, 16:21

... discussions can get heated, and some even turn vicious But I've been around long enough to realize that heat and hate always accompany a genuine paradigm shift, even in something as apolitical as strength ... strength training When one of my articles gains traction, it's usually because I've challenged a long-practiced and long-accepted idea A few years ago, for example, everyone agreed that the best way ... aLL have someone in our lives who affects us immeasurably Maybe that person is a parent, teacher, or friend Maybe that person gave us just enough encouragement at a critical moment, even if at...

Ngày tải lên: 22/03/2014, 16:21

... calculation 4.1 Suppose we are drawing a triangle with a graduated rule and a protractor: we take the polar angle of OA, say , and set OA = ; next we take the angle (OA, AB), say , and set AB = ... the area of the triangle, the formula area(OAB) = [area(OAB)] = + sin(1 2 sin + ) yields 2 2 (1 + sin ) The proportional error on the triangle area ( [area(OAB)])1/2 = area(OAB) reaches a minimum ... errors The choice of a relevant mathematical language for speaking about errors and their propagation is an old topic and one that has incited a large variety of works Without retracing the whole...

Ngày tải lên: 24/03/2014, 04:20

... the phase approximation, that is, the phase of (7) arg H e jω , p = −Nω − arg A e jω , p where p is the parameter used to adjust fractional delay and N denotes the order of the designed allpass ... International Symposium on Circuits and Systems, pp 2641–2645, May 1998 [7] T I Laakso, V V¨ lim¨ ki, M Karjalainen, and U K Laine, a a “Splitting the unit: delay tools for fractional delay filter ... using a a fractional delay filters, Doctoral thesis, Helsinki University of Technology, Espoo, Finland, 1995 [15] M Makundi, T I Laakso, and V V¨ lim¨ ki, “Efficient tunable a a IIR and allpass filter...

Ngày tải lên: 21/06/2014, 07:20

... r[max, v], majcode) if yi = 1, i < n − Acknowledgments I am grateful to N Bakhytjan and A Jumadildayeva for assistance in making calculations, and to the anonymous referee for essential remarks ... bi-statistics (f, majcode), (f, scode), counter-examples appear at n = Main Lemmas For a coding word α = α1 αn ∈ En , we say that i is a right-maximal index and αi is a right-maximal value ... for all compositions I = (i1 , , ir ) [5] When A is an ordered alphabet, Sn (A) can be realized as the sum of all nondecreasing words in An The commutative image of Sym is the algebra of...

Ngày tải lên: 08/08/2014, 12:22

... research The following additional data are available with the online version of this paper Additional data file demonstrates a full end-to-end analysis of the protein interaction datasets Additional ... reciprocated FN observations is PFN n Software implementation and availability The R/Bioconductor packages used in the statistical analysis in this report are all available as freely distributed and ... 12:1353-1365 Zhao R, Davey M, Hsu Y, Kaplanek P, Tong A, Parsons A, Krogan N, Cagney G, Mai D, Greenblatt J, et al.: Navigating the chaperone network: an integrative map of physical and genetic interactions...

Ngày tải lên: 14/08/2014, 08:20