How Do You Calculate The Overall Heat Transfer Coefficient For Shell And Tube Heat Exchanger?

What affects the heat transfer coefficient?

The factors affecting overall heat transfer coefficient are : Physiochemical properties of fluids ( both cold and hot ) such a viscosity , density, specific heat, thermal conductivity.

Geometry of the exchanger ( equivalent length and heat exchanging area ) Velocity of flowing fluids..

How do you calculate the heat transfer area of a shell and tube heat exchanger?

4.0 – HEAT EXCHANGERS CALCULATIONS:The main basic Heat Exchanger equation is: Q = U x A x ΔTm =The log mean temperature difference ΔTm is: ΔTm =(T1 – t2) – (T2 – t1) = °F.T1 = Inlet tube side fluid temperature; t2 = Outlet shell side fluid temperature;ln (T1 – t2) (T2 – t1)

Shell and tube heat exchangers are the most common kind of heat exchangers used in the cooling of both liquids and gasses. They thank their popularity to their design flexibility allowing a wide variety of temperatures, pressures and mediums used.

What is the overall heat transfer coefficient?

The overall heat transfer coefficient, or U-value, refers to how well heat is conducted through over a series of resistant mediums. Its units are the W/(m2°C) [Btu/(hr-ft2°F)].

What are the two types of heat exchangers?

There are two main types of regenerative heat exchangers—static heat exchangers and dynamic heat exchangers.

What does the heat transfer coefficient depend on?

Heat transfer coefficient depends on both the thermal properties of a medium, the hydrodynamic characteristics of its flow, and the hydrodynamic and thermal boundary conditions.

How do you calculate the heat transfer coefficient of a heat exchanger?

Composition= the overall heat transfer coefficient (W/(m2•K))= the contact area for each fluid side (m2) (with and expressing either surface)= the thermal conductivity of the material (W/(m·K))= the individual convection heat transfer coefficient for each fluid (W/(m2•K))= the wall thickness (m).

How do you create a shell and tube heat exchanger?

Most shell-and-tube heat exchangers are either 1, 2, or 4 pass designs on the tube side. This refers to the number of times the fluid in the tubes passes through the fluid in the shell. In a single pass heat exchanger, the fluid goes in one end of each tube and out the other.

What is heat transfer area?

The heat transfer coefficient is the heat transferred per unit area per kelvin. Thus area is included in the equation as it represents the area over which the transfer of heat takes place. The areas for each flow will be different as they represent the contact area for each fluid side.

How do you calculate the number of passes on a heat exchanger?

The distance between two baffles is baffle spacing. Shell-and-tube heat exchangers can have multiple passes, such as 1-1, 1-2, 1-4, 1-6, and 1-8 exchangers, where the first number denotes the number of the shells and the second number denotes the number of passes.

How many tubes are in a tube and shell heat exchanger?

9600 tubesCan a heat exchanger contain 9600 tubes? It is a shell and tube heat exchanger.

What are the 4 types of heat transfer?

Various heat transfer mechanisms exist, including convection, conduction, thermal radiation, and evaporative cooling.

Can the overall heat transfer coefficient be negative?

Thermal Convection The algebraic sign of Newton’s Law of Cooling is positive for T∞ > Ts (heat transfer into the object) and negative when T∞ < Ts (heat transfer out of the object). The convective heat transfer coefficient h is usually a positive, experimentally determined value.

How do you determine the number of tubes on a heat exchanger?

Be sure to adjust all flowrates and velocities for the number of tubes AND the number of tube passes. If an exchanger has 200 tubes in 2 passes, the total flow will be moving through 100 tubes at a time; if there are 4 passes, it will go through 50 tubes.

How do you calculate Reynolds number in heat exchanger?

The Reynolds number (Re) of a flowing fluid is calculated by multiplying the fluid velocity by the internal pipe diameter (to obtain the inertia force of the fluid) and then dividing the result by the kinematic viscosity (viscous force per unit length).

What is heat transfer formula?

Q=m \times c \times \Delta T Here, Q is the heat supplied to the system, m is the mass of the system, c is the specific heat capacity of the system and \Delta T is the change in temperature of the system. The transfer of heat occurs through three different processes which are, Conduction, Convection, and Radiation.