Q. In how many categories heat exchangers are classified on the basis of physical state of heat exchanging fluids?

View solution

Q. Many types of heat exchangers have been developed to meet the widely varying applications. Based upon their

(i) Operating principle
(ii) Arrangement of flow path
(iii) Design

Identify the correct statements

View solution

Q. How many fluids remain at constant temperature during the process of boiling and condensation?

View solution

Q. Identify the correct expression for effectiveness

View solution

Q. In a gas turbine recuperator, the capacity ratio becomes

View solution

Q. In a gas turbine recuperator, the expression for effectiveness for the parallel flow configuration reduces to

View solution

Q. What is the maximum efficiency for parallel flow heat exchanger?

View solution

Q. The curve of effectiveness versus NTU parameters indicates the relationship between

(i) Effectivenes
(ii) NTU MAX
(iii) C MIN/C MAX

Identify the correct statements

View solution

Q. Hot water having specific heat 4200 J/kg K flows through a heat exchanger at the rate of 4 kg/min with an inlet temperature of 100 degree Celsius. A cold fluid having a specific heat 2400 J/kg K flows in at a rate of 8 kg/min and with inlet temperature 20 degree Celsius. Make calculations for maximum possible effectiveness if the fluid flow conforms to parallel flow arrangement

View solution

Q. A counter flow heat exchanger is used to col 2000 kg/hr of oil (c p = 2.5 k J/kg K) from 105 degree Celsius to 30 degree Celsius by the use of water entering at 15 degree Celsius. If the overall heat transfer coefficient is expected to be 1.5 k W/m² K, find out the water flow rate. Presume that the exit temperature of the water is not to exceed 80 degree Celsius

View solution

Q. Assumptions made for calculation of logarithmic mean temperature difference are

(i) Constant overall heat transfer coefficient
(ii) The kinetic and potential energy changes are negligible
(iii) There is no conduction of heat along the tubes of heat exchanger

Identify the correct statements

View solution

Q. A cold fluid (specific heat 2.95 k J/kg K) at 10 kg/min is to be heated from 25 degree Celsius to 55 degree Celsius in a heat exchanger. The task is accomplished by extracting heat from hot water (specific heat 4.186 k J /kg K) available at mass flow rate 5 kg/min and inlet temperature 85 degree Celsius. Identify the type of arrangement of the heat exchanger

View solution

Q. In a food processing plant, a brine solution is heated from – 12 degree Celsius to – 65 degree Celsius in a double pipe parallel flow heat exchanger by water entering at 35 degree Celsius and leaving at 20.5 degree Celsius. Let the rate of flow is 9 kg/min. Estimate the area of heat exchanger for an overall heat transfer coefficient of 860 W/m² K. For water c P = 4.186 * 10³ J/kg K

View solution

Q. Exhaust gases (c P = 1.12 k J/kg K) flowing through a tubular heat exchanger at the rate of 1200 kg/hr are cooled from 400 degree Celsius to 120 degree Celsius. This cooling is affected by water (c P = 4.18 k J/kg K) that enters the system at 10 degree Celsius at the rate of 1500 kg/hr. If the overall heat transfer coefficient is 500 k J/m² hr degree, what heat exchanger area is required to handle the load for parallel flow arrangement?

View solution

Q. A steam condenser is transferring 250 k W of thermal energy at a condensing temperature of 65 degree Celsius. The cooling water enters the condenser at 20 degree Celsius with a flow rate of 7500 kg/hr. Calculate the log mean temperature difference

View solution

Q. For what value of end temperature difference ratio, is the arithmetic mean temperature difference 5% higher than the log-mean temperature difference?

View solution

Q. A company is heating a gas by passing it through a pipe with steam condensing on the outside. What percentage change in length would be needed if it is proposed to triple the heating capacity?

View solution

Q. A steam condenser is transferring 250 k W of thermal energy at a condensing temperature of 65 degree Celsius. The cooling water enters the condenser at 20 degree Celsius with a flow rate of 7500 kg/hr. If overall heat transfer coefficient for the condenser surface is 1250 W/m² K, what surface area is required to handle this load?

View solution

Q. Exhaust gases (c P = 1.12 k J/kg K) flowing through a tubular heat exchanger at the rate of 1200 kg/hr are cooled from 400 degree Celsius to 120 degree Celsius. This cooling is affected by water (c P = 4.18 k J/kg K) that enters the system at 10 degree Celsius at the rate of 1500 kg/hr. If the overall heat transfer coefficient is 500 k J/m² hr degree, what heat exchanger area is required to handle the load for counter flow arrangement?

View solution

Q. What is the value of specific heat for brick in J/kg K?

View solution