Flow rate of coolant

Rework Problem P8-6 for the case when heat is removed by a heat exchanger jacketing the reactor. The flow rate of coolant through the jacket is sufficiently high that the ambient exchanger temperature is constant at 50°C. 

Gc = flow rate of coolant (mass per unit area per unit time)... 

The design issues of thermal management sub-system depend on the total produced heat and of consequence on the sizing of the stack. The mass flow rate of coolant (usually deionised water) can be derived by the definition of thermal capacity described by the following equation ... 

To calculate the maximum steady-state heat removal capacity, we assume that the cooling-water flow rate at design is 25 percent of its maximum. Thus, when the control valve is wide open, four times the design flow rate of coolant is available. We also assume that the reactor temperature is held at its specified value. The steady-state heat transfer rate under these conditions can be calculated from the following equations ... 

This can be seen in the simulation of the PID control of polymerization reactor temperature by Houston and Schork [34]. Reactor temperature is often controlled by manipulating the temperature or flow rate of coolant in the reactor cooling jacket. This scheme is hindered by the slow dynamics of heat removal and the nonlinear nature of the heat evolution process (especially in... 

Flow rate is controlled by a valve on the outlet, which can be either manually or automatically controlled, hi the case of automatic control it can adjust in response to the level in the buffer tank. The temperature of pasteurisation is controlled by adjusting the temperature of the heating medium. This can be linked to a PU controller which calculates the temperature required in relation to the flow rate. The outlet tanperature of the beer needs to be at a level suitable for packaging and is controlled by adjusting the flow rate of coolant... 

Of the data needed for the calculation, the decay constant X of the relevant fission product and the circulating primary coolant massm are known. The purification constant e can be calculated from the following formula for the fractional flow rate of coolant to the purification system (degasifler, mixed-bed ion exchanger), taking into account the purification factor F ... 

A high flow rate of coolant in natural circulation, which assures efficient core cooling and heat removal under routine and emergency conditions, including design basis and beyond design basis accidents ... 

The functional relationship between the mass flow rate of coolant and the controller output is usually given by the controller manufacturer, or can be determined experimentally. Figure 4.7 gives the control valve characteristic curve determined for this system. The fraction controller output is related to the proportional gain through... 

F = molar flow rate (mol/time) of key species m = mass flow rate of coolant M= mass flow rate of reacting fluid Tc coolant temperature y = conversion... 

A PID controller is used to control the temperature of a jacketed batch reactor by adjusting the flow rate of coolant to the jacket. The temperature controller has been tuned to provide satisfactory control at the nominal operating conditions. Would you anticipate that the temperature controller may have to be retuned for any of the following instrumentation changes Justify your answers. 

The reactor contains a cooling coil to remove heat. The heat-transfer area of the coil is 2.0 m. The overall heat-transfer coefficient between the coil and the reactor contents is 200,000 cal/m -h-°C. The flow rate of coolant through the coil is very high the coolant enters and leaves at 32 °C. 

A.3 Flow Rate of Coolant Through a Mold Base. Coolant lines of 1.27 cm in diameter are machined in the base of a mold with a spacing of 3.81 cm (this is the centerline distance) and a distance of 2.54 cm from the mold surface. The total length of the line is 1.83 m. Tap water is used as the coolant and enters the line at 12 °C with a line pressure of 1x10 Pa. The coolant must remove heat at the rate 1758.3 J/s. The mold base is made of stainless steel with the thermal properties given in Problem 10A.2. Determine the convection heat transfer coefficient in the coolant lines, the increase in temperature of the water (i.e., the temperature of water at the exit of the... 

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